Question 11 - Figure it out - Page 176, 177 - Chapter 7 Class 8 - Proportional Reasoning-1(Ganita Prakash)

Transcript

Question 11 A tractor can plough the same area of a field 4 times faster than a pair of oxen. A farmer wants to plough his 20-acre field. A pair of oxen takes 6 hours to plough an acre of land. How much time would it take if the farmer used a pair of oxen to plough the field? How much time would it take him if he decides to use a tractor instead?Given that A pair of oxen takes 6 hours to plough an acre of land Since farmer wants to plough his 20-acre field Time taken by pair of oxen = 20 acres × 6 hours/acre = 120 hours Using Tractor The tractor is 4 times faster, so it takes 1/4 of the time per acre. Oxen time per acre =6 hours. Tractor time per acre =𝟔÷𝟒=𝟏.𝟓 hours. Thus, Total Tractor Time = 20 acres × 1.5 hours/acre =𝟑𝟎 hours. Thus, Pair of oxen take 𝟏𝟐𝟎 hours; Tractor takes 𝟑𝟎 hours.