W is directly proportional to U. If W = 5 when U = 3, find U when W = 2/7
-
6/35
- 10/21
- 21/10
- 35/6
The correct answer is: A
Explanation
\(W ∝ U\\
W = KU\\
K = \frac{W}{U}\\
K = \frac{5}{3}\\
W = \frac{5}{3}U\\
\frac{2}{7} = \frac{5}{3}U\\
U = \frac{2}{7} \times \frac{3}{5}\\
U = \frac{6}{35}\)
There is an explanation video available .