ESAT Specimen Test Question 11

Can someone help explain this question to me. The answer is 49%

Two variables are connected by the relation:

P proportional to 1 over Q squared

Q is increased by 40%.

What is the percentage change in P to the nearest whole number?

Reply 1

jasminhayes36

P = k / (Q₁²)
If Q increases by 40%, Q₂ = 1.4Q₁
P = k / Q₂² = k / (1.4Q₁)².
P = k / 1.96Q₁²
0.51P = k / Q₁²
So, P has changed to 0.51P, which is equivalent to a 49% change.

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