Question

7. Choose the correct answer. If there is direct variation and y= 27 when t= 4, find y when = 12.

a. 9

b. 0.56

c. 81

d. 1.78​

Answer 1

c

Explanation:

Given direct variation between y and t , then the equation relating them is

y = kt ← k is the constant of variation

To find k use the condition y = 27 when t = 4 , then

27 = 4k ( divide both sides by 4 )

6.75 = k

y = 6.75t ← equation of variation

When t = 12 , then

y = 6.75 × 12 = 81