How many paying stones, each measuring 2 1/2 m $\times$ 2 m are required to pave a rectangular court yard 30 m long and 16 1/2 m board?
99
90
95
100
Explanation:
30 $\times\frac{33}{2}$ =$\dfrac{5}{2}$ $\times$ 2 $\times x$ => x = 99