If x varies directly to y and if x = 3, y = 5, then find the value of y when x = 7.8.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 13.
x varies directly as y
Formula: y = k × x
k = y ÷ x = 5 ÷ 3
Now, y = (5 ÷ 3) × 7.8
y = (5 ÷ 3) × (39 ÷ 5) = 39 ÷ 3 = 13