Mental Maths Questions and Answers: Data Handling | Mental Math for Class 7 PDF Download

Q1: Find the arithmetic mean of the numbers -3, 0, -4,8,11.
Ans: 2.4

Q2: Find the mean of the first ten natural numbers.
Ans: 5.5

Q3: Find the mean of first ten whole numbers.
Ans: 4.5

Q4: Find the mean of prime numbers between 10 and 20.
Ans: 15

Q5:If the mean of 3, 1, 5, x and 9 is 4, then find the value of x.
Ans: 2

Q6: Given that the mean of five numbers is 28. If one of the numbers is excluded, the new mean becomes 25. Determine the excluded number.
Ans: 40

Q7: The mean of five observations is 15. If the mean of the first three observations is 14 and that of the last three is 17, find the third observation.
Ans: 18

Q8: Find the mean of fist nine even numbers.
Ans: 10

Q9: Gunika secured 73, 86, 78 and 75 marks in four tests. What is the least number of marks she should secure in her next test if she has to have a mean score of 80 marks in five tests?
Ans: 88

Q10: If the mean of x + 2, x + 4, x + 6 is 15. Find x.
Ans: 11

Q11: Find the range of the following data: 21, 6, 17, 18, 12, 8, 4, 13.
Ans: 17

Q12: Komal worked for  hours on Monday,  hours on Tuesday and  hours on Wednesday. What is the mean number of hours she worked on these three days?
Ans:

Q13: The mean weight of a class of 20 students is 48 kg. Two more students weighing 60 kg and 58 kg respectively join the class. What is the mean weight of the class now?
Ans: 49kg

Q14: Find the mean of all factors of 24.
Ans: 7.5

Q15: Find the mean of first eight multiples of 5.
Ans: 22.5

Q16: Radha scored 97, 73 and 88 respectively in her first three examinations. If she scored 80 in her fourth examination, then by how much will her mean score increase or decrease?
Ans: Decrease by 1.5

Q17: The mean, median and mode of four numbers is 8. The smallest number is 7. Find the number.
Ans: 7, 8, 8, 9

Q18: The mean of three numbers a, b and c is 8, and the mean of five numbers a, b, c, d and e is 15. Find the mean of d and e.
Ans: 25.5

Q19: Following cards are put facing down

What is the probability of drawing out?
(a) a vowel
(b) A or I
(c) U
(d) a consonant
Ans: 

Q20: A card is drawn from a pack of 100 cards numbered 1 to 100. Find the probability of drawing a square number.
Ans: 1/10

Q21: The probability of winning a game is 0.07. What is the probability of losing it?
Ans: 0.93

Q22: A dice is thrown once. What is the probability that the numbers shown on the dice is
(i) an odd number
(ii) a prime number
(iii) a composite number
(iv) a multiple of 2
(v) a factor of 6
(vi) a number greater than 6.
(vii) a number less than 3.
Ans:
(i) 1/2
(ii) 1/2
(iii) 1/3
(iv) 1/2
(v) 2/3
(vi) 0
(vii) 1/3

Q23: Find the median for the following set of numbers: 6, 2, 5, 4, 3, 4, 4, 2, 3
Ans: 4

Q24: If 17 is taken from the following data, then find the new median. 12, 26, 17, 28, 10, 14, 15, 32, 35.
Ans: 20.5

Q25: The mean of seven numbers is 25. If each number is divided by 2, what will be the new mean?
Ans: 12.5

Q26: The mean of 200 items was 50. Later on it was discovered that the two items were misread as 92 and 8 instead of 192 and 68. Find the correct mean.
Ans: 50.8

Q27: Find the median of the given data if the mean is 4.5.
5, 7, 7, 8, x, 5, 4, 3, 1, 2.
Ans: 4.5

Q28: The mean of three numbers is 10. The mean of other four numbers is 12. Find the mean of all the numbers
Ans: 

Q29:The following observations have been arranged in ascending order. 29, 32, 48, 50, x, x + 2, 72, 78, 82, 96
If the median of the data is 61, find the value of x.
Ans: 60

Q30: What is the probability of the sun setting tomorrow?
Ans: 1

Q31: What is the probability that a student chosen at random out of 3 girls and 4 boys is a boy?
Ans: 4/7

Q32: Find the mode of the ages (in years) of 10 students of class VII. 13, 12, 14, 12, 13, 12, 14, 12, 13, 14.
Ans: 12

Q33: A coin is tossed 100 times with the following frequencies:
Head: 49, Tail: 51, When a coin is tossed at random, what is the probability of getting a Head?
Ans: 0.49

Q34: A box contains two pairs of socks of two different colours (black and white). I have picked out a black sock. I pick out one more with my eyes closed. What is the probability that it will make a correct pair?
Ans: 1/3

Q35: What is the class mark of the class 30 - 35?
Ans: 32.5

Direction (36 to 38): The weight of new born babies (in kg) in a hospital on a particular day are as follows: - 2.1, 2.4, 3.8, 3.0, 2.6, 2.1, 1.9, 3.7, 2.6

Q36: Find the range.
Ans: 1.9kg

Q37: Find the median  weight.
Ans: 2.6kg

Q38: How many babies weigh more the median weight?
Ans: 3 babies

Q39: Find the median of first 10 even  numbers.
Ans: 11

Q40: Find the median of first 50 whole numbers.
Ans: 24.5

Direction (41 to 43): Use the bar graph below to answer the questions.

Q41: What is the range of marks scored by the students?
Ans: 40

Q42: How many student score above 70 but less than 90?
Ans: 13 students

Q43: If the pass score was 70, how many students did not pass?
Ans: 3 students

Q44: The mean of Shivansh's marks in 5 subjects is 86. He got 80 marks in the 6th subject. What is the mean of his marks in all the 6 subjects together?
Ans: 85

Q45: A circle is shaded as shown below and Aamir throws a dart at it. What is the probability that the dart will hit the shaded part?

Ans: 5/12

Q46: What is the probability of getting a number 10 on throwing a dice?
Ans: 0

Q47: Six of 24 students in a class are left-handed. What is the probability that randomly selected student is right-handed?
Ans: 3/4 = 0.75

Direction (48 to 50): The following graph shows the points scored in four games of basketball. Study the graph.

Q48: What is the lowest score? Who scored it and in which game?
Ans: Lowest score =4, scored by team B in 3^rd game

Q49: By how many points did team A win in the first game?
Ans: 12 points

Q50: By how many points did the team B win in the fourth game?
Ans: 4 points

For detail explanation of solutions refer to the videos provided