Question

The value of y varies directly with x, and y = 18 when x = 12. Find y when x = 60.

a) y = 42
b) y = 1.5
c) y = 40
d) y = 90

Answer 1

To find y when x = 60 given that y varies directly with x and y = 18 when x = 12, we first find the constant of variation (k = 1.5) and then apply it to determine that y = 90 when x = 60.

Step-by-step explanation:

To find the value of y when x is 60, given that y varies directly with x and y = 18 when x = 12, we use the concept of direct variation. In direct variation, we can describe the relationship between y and x using the formula y = kx, where k is a constant.

First, we need to find the constant of variation (k) using the values provided:

1. y = kx (Direct variation formula)
2. 18 = k × 12 (Substitute given values)
3. k = 18 / 12
4. k = 1.5

Now, we use the constant k to find y when x = 60:

1. y = kx
2. y = 1.5 × 60
3. y = 90

Therefore, the value of y when x = 60 is 90.