If $0 < x <1000$ and [x] denotes the greatest integer less than or equal to x, then the number of possible values of x satisfying $[\frac{x}{2}]+[\frac{x}{3}]+[\frac{x}{5}]=\frac{31}{30}x$, is |
34 32 33 none of these |
33 |
We have, $[\frac{x}{2}]+[\frac{x}{3}]+[\frac{x}{5}]=\frac{31}{30}x$ $⇒[\frac{x}{2}]+[\frac{x}{3}]+[\frac{x}{5}]=\frac{x}{2}+\frac{x}{3}+\frac{x}{5}$ $⇒[\frac{x}{2}]=\frac{x}{2},[\frac{x}{3}]=\frac{x}{3}$ and $[\frac{x}{5}]=\frac{x}{5}$ $⇒\frac{x}{2},\frac{x}{3},\frac{x}{5}$ are all integers ⇒ x is a multiple of the LCM of 2, 3, 5. ⇒ x is a multiple of 30. Also, $0 < x <1000$. $∴x = 30, 60, 90,...., 990$ or, $x = 30 × 1, 30 × 2, 30 × 3,...., 30 × 33$ Hence, there are 33 values of x. |