Q1:Anita is 6 years older than her brother Vikram. If Vikram is 10 years old, how old is Anita?
Sol:
Anita’s age = Vikram’s age + 6
= 10 + 6
= 16 years
Q2: A store sells mangoes at ₹30 each and bananas at ₹10 each. What is the total cost of purchasing 4 mangoes and 3 bananas?
Sol:
Cost of 4 mangoes = 4 × ₹30 = ₹120
Cost of 3 bananas = 3 × ₹10 = ₹30
Total cost = ₹120 + ₹30 = ₹150
Q3: The perimeter of a square is calculated as 4 times the side length. If the side length is 8 cm, what is the perimeter?
Sol: Perimeter = 4 × side length
= 4 × 8
= 32 cm
Q4: A car travels at a speed of 15 km per hour. How far does it travel in 4 hours?
Sol:
Distance = Speed × Time
= 15 × 4
= 60 km
Q5:If y represents a number, what expression represents 5 more than three times the number?
Sol:
Three times the number = 3y
5 more than three times the number = 3y + 5
Q6: A garden hose is 12 meters long. An additional hose of length n meters is connected to it. Write an expression for the total length. If n = 5 meters, find the total length.
Sol:
Expression for total length = 12 + n
For n = 5 meters:
Total length = 12 + 5 = 17 meters
Q7: A bakery sells muffins at ₹25 each and brownies at ₹15 each. Write an expression for the total cost of buying m muffins and b brownies. Calculate the cost for 6 muffins and 2 brownies.
Sol:
Expression for total cost = 25m + 15b
For m = 6 and b = 2:
Total cost = (25 × 6) + (15 × 2) = 150 + 30 = ₹180
Q8: Simplify the expression: 6a + 3b - 2a + 5b - 9.
Sol:
Combine like terms:
= (6a - 2a) + (3b + 5b) - 9 =
= 4a + 8b - 9
Q9: In a quiz, a student earns 3x points for each correct answer and loses y points for each incorrect answer. Over three rounds, their scores are 3x - y, 2x - 2y, and 4x - 3y. Write and simplify an expression for the total score. If x = 4 and y = 2, calculate the total score.
Sol:
Total score = (3x - y) + (2x - 2y) + (4x - 3y)
= (3x + 2x + 4x) + (-y - 2y - 3y)
= 9x - 6y
For x = 4 and y = 2:
Total score = (9 × 4) - (6 × 2) = 36 - 12 = 24
Q 10: Subtract the expression 5x - 3y + 7 from 8x + 2y - 4. Evaluate the resulting expression if x = 3 and y = 2.
Sol:
Subtract: (8x + 2y - 4) - (5x - 3y + 7)
= (8x - 5x) + (2y - (-3y)) + (-4 - 7)
= 3x + 5y - 11
For x = 3 and y = 2:
Result = (3 × 3) + (5 × 2) - 11 = 9 + 10 - 11 = 8
41 videos|251 docs|8 tests
|
1. What is an expression using letter-number, and how is it used in mathematics? | ![]() |
2. How can I simplify expressions that involve letters and numbers? | ![]() |
3. What are some common mistakes to avoid when working with letter-number expressions? | ![]() |
4. Can you provide an example of a real-world application of expressions using letter-number? | ![]() |
5. How do letter-number expressions relate to algebraic equations? | ![]() |