Answer:
40% decrease
Step-by-step explanation:
Say the percent decrease is x%. Then, we can write the equation:
65 - x% * 65 = 39
Notice that 65 is a common factor of both terms on the left, so factor that out:
65 * (1 - x%) = 39
Divide by 65 on both sides:
1 - x% = 0.6
Subtract 0.6 from and add x% to both sides:
x% = 0.4
Remember that % simply means "out of 100", so x% = x/100:
x/100 = 0.4
Multiply by 100:
x = 40
So the percentage decrease is 40%, or the percent increase is -40% (whichever way the question asks).
Hope this helps!
