Q1: 10 meters of cloth cost Rs 1000. What will 4 meters cost?
(a) Rs 400
(b) Rs 800
(c) Rs 200
(d) Rs 100
Ans: (a)
10/1000 = 4/x
= x = 400
Q2: If x = 20 and y = 40, then x and y are:
(a) Directly proportional
(b) Inversely proportional
(c) Neither directly nor inversely proportional
(d) Cannot be determined
Ans: (a)
x = 20 and y = 40
Clearly, 40 = 2 x 20
y = 2x
y∝x, where 2 is the proportionality constant.
Q3: If x and y are directly proportional, then which of the following is correct?
(a) x+y=constant
(b) x-y=constant
(c) xy=constant
(d) x/y=constant
Ans: (d)
x∝y
x=ky
k=x/y, where k is a constant.
Q4: The weight of 12 sheets of thick paper is 40 grams, how many sheets of the same paper would weigh 2500 grams?
(a) 750
(b) 800
(c) 850
(d) 950
Ans: (a)
For 12 sheets, the weight of the paper is 40 grams
Let a number of sheets for 2500 is x.
Using direct proportion concept:
12/40 = x/2500
x=(12×2500)/40
x=750
Q5: If x and y are inversely proportional, then which one is true?
(a) x1/y1 = x2/y2
(b) x1 /x2 = y1/y2
(c) x1 /x2 = y2/y1
(d) x1 .x2 = y1.y2
Ans: (c)
∝1/y
x=k(1/y)
xy=k
x1y1 = x2y2
x1/x2 = y2/y1
Q6: If 12 workers can build a wall in 50 hours, how many workers will be required to do the same work in 40 hours?
(a) 10
(b) 13
(c) 14
(d) 15
Ans: (d)
12 × 50 = x × 40
x = (12×50)/40
= 15
Q7: If 300 Kg of coal cost 6000₹, then find the cost of 120 kg of coal?
(a) 1200₹
(b) 2400₹
(c) 3200₹
(d) 4200₹
Ans: (b)
total weight =300kg
cost of 1 kg = 6000/300
= 20rupees 120kg
= 20 × 120 = 2400rupees
Q8: If it takes 40 days for 120 men to complete a work, how long will it take for 80 men to complete the same work?
(a) 50 days
(b) 60 days
(c) 80 days
(d) 100 days
Ans: (b)
40 × 120 = 80 × x
⇒ x = 60
Q9: A car takes 18 hours to ride 720 kilometers. Time taken by the car to travel 360 kilometers is:
(a) 10 hours
(b) 11 hours
(c) 9 hours
(d) 16 hours
Ans: (c)
720/18 = 360/x
x = 9 hours
Q10: The scale of a map is given as 1: 300. Two cities are 4 km apart on the map. The actual distance between them is:
(a) 1000 km
(b) 1100 km
(c) 1200 km
(d) 1300 km
Ans: (c)
1 : 300 = x : y
1/300 = 4/y
y = 4 x 300 = 1200
Hence, the distance between the two cities is 1200 km.
79 videos|408 docs|31 tests
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1. How can direct and inverse proportions be distinguished? |
2. What is the relationship between direct proportion and inverse proportion? |
3. How can direct and inverse proportions be represented mathematically? |
4. Can a relationship exhibit both direct and inverse proportions simultaneously? |
5. How can direct and inverse proportions be applied in real-life scenarios? |
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