20. Three mark exercise problems V

1. The product of $2$ two digit numbers is $300$ and their HCF is $5$. What are the numbers?

 

 

The two numbers are (5,60)(60,2)(15,20)(10,30).

 

2. Wilson, Mathan and Guna can complete one round of a circular track in $10$, $15$ and $20$ minutes respectively. If they start together at $7 \ a.m$ from the starting point, at what time will they meet together again at the starting point?

 

 

Wilson, Mathan and Guna will meet together again at After $60$ minutes, at $8 \ a.m$After $3$ hours at $10 \ a.m$After $25$ minutes, at $7:25 \ a.m$After $6$ hours at $1 \ p.m$