Question 27 & 28
Question 27: A train is 360 m long and is running with speed of 45 km /hr. In how much time it will cross a bridge of length 140 meter?
Solution:
The train will enter bridge from one end and will cover a distance equal to length of bridge and will reach other end of bridge. Then it will cross bridge completely after covering distance equal to its own length- and then its last boggy will be out from other end !
So, train has to cover total distance equal to its length + length of bridge = 360+140=500 meters;
Using formula;
So, the train will cross the bridge in 40 seconds
Question 28: There are 5 children. Every next child is 3 years older than the previous younger one. If sum of their ages is equal to 50 years find the age of the youngest child.
Solution:
Let age of youngest child is ‘x’; every next child is 3 years elder than previous one – so;
There ages sum;
It is given equal to 50 i-e;
So, the age of the youngest child is 4 years