Q22 of 24 Page 213

If 10 men working 7 hrs a day dig a trench 147 m long; how many men working 8 hrs a day will dig a trench 160 m long?

Working 7 hours a day 147 m long trench can be dug by 10 men.


Working 1 hour a day 147 m long trench can be dug by


= 10 x 7 = 70


Working 1 hour a day 1 m long trench can be dug by


Working 8 hours a day 1 m long trench can be dug by


Working 8 hours a day 160 m long trench can be dug by


= 9.523


As the men cannot be in decimal or fraction, so, rounding off we get 10 men.


So, it would take 10 men working 8hr a day to dug 160m trench.


More from this chapter

All 24 →
20

The sides of a rectangle are 20cm and 15cm. If each side of the rectangle is increased by 20% find the percentage increase in the area?

 21

Jenny and Sally bought a special 360-day joint membership at a tennis club. Jenny will use the club every alternate day and sally will use the club every third day. They both use the club on the first day. How many days will neither person use the club in the 360 days?

 23

In a hostel, it costs Rs.1800 to keep 50 children for 8 weeks. For what length of time did the cost of keeping 90 children amount to Rs. 2160.

 24

If a compound ratio is 7:5 and 8:x is 84:60 find x.