Problem Solving (PS) | Re: The grass in a field grows in a constant rate. If 240 sheep were to gr

Non Algebraic method - Using options

Let 240 sheep in 5 weeks eat 240x5 x g = 1200g (Amount of grass)
Let 200 sheep in 7 weeks eat 200 x 7 x g = 1400g
Therefore in two weeks 200g of extra grass has grown, i.e 100g grows per week (Since grass grows at a constant rate)

So 170 sheep in how many weeks will make the grass bare?
Lets look at the options..
If we consider 9 weeks, extra grass from 7th week onwards is 200g , so total grass = 1600g
But 170 x 9 not equal to 1600

If we consider 10 weeks, extra grass from 7th week onwards is 300g, so total grass = 1700g
170 x 10 = 1700.
Therefore correct answer = 10 weeks