Question

In making 1000 revolutions, a wheel covers 88 km. The diameter of the wheel is

(a) 140 (b) 150 (c) 160 (d) 166

Answer 1

Distance covered in 1000 revolution= 88km = 88000m
now,
1000 revolutions covers 88000m
1 revolution covers $\frac{88000}{1000}=88m$
now
distance covered in 1 revolution = circumference of wheel = 88m

ie, $\pi \times d=88$

$\frac{22}{7}\times d=88$

$d=88\times \frac{7}{22}$

$d=28m$