Question

Three cars A, B and C started from a point at
5 p.m., 6 p.m. and 7 p.m. respectively and
travelled at uniform speeds of 60 km/hr,
80 km/hr and x km/hr respectively in the same
direction. If all the three met at another point
at the same instant during their journey, then
what is the value of x ?​

Answer 1

Answer:

The value of X is 120 Km/hr.

Given:

Three cars A, B and C started from a point at 5 p.m., 6 p.m. and 7 p.m. respectively and travelled at uniform speeds of 60 km/hr,80 km/hr and x km/hr respectively in the same  direction.

To find:  

If all the three met at another point at the same instant during their journey, then

what is the value of x ?

Solution:

The LCM of 60 and 80 is

60 = 2 $\times 2 \times 3 \times$ 5

80 = 2 $\times 2 \times 2 \times 2 \times$ 5

LCM = 240

Consider they are meeting after 4 hours from 5 pm, at 9 pm

A would have travelled 60$\times$4 = 240

B would have travelled 80 $\times$ 3 = 240

X would have travelled x $\times$  2 = 240

X = 120 km/hr.