Question:
Both u and v vary directly with each other. When u is 10, v is 15, which of the following is not a possible pair of corresponding values of u
and v?
(a)2 and 3
(b) 8 and 12
(c) 15 and 20
(d) 25 and 37.5
Solution:
(c) Since, $u$ and $v$ vary directly, i.e. $u / v=k$ (constant)
If $u=10$ and $v=15$, then, $\frac{u}{v}=\frac{10}{15}=\frac{2}{3}$
In option (b), $\frac{8}{12}=\frac{2}{3}$
In option (c), $\frac{15}{20}=\frac{3}{4}$
In option (d), $\frac{25}{37.5}=\frac{2}{3}$
So, option (c) is not a possible pair of corresponding values of $u$ and $v$. Hence, option (c) is correct.