To solve this problem, we need to find the equivalent single increase in price that would result in the same final price as the double increase of 15% followed by 40%.
Let's assume the original price of the baseball gloves is $100.
After the first increase of 15%, the price becomes:
$100 + 15% of $100 = $100 + $15 = $115.
After the second increase of 40%, the price becomes:
$115 + 40% of $115 = $115 + $46 = $161.
So, the final price after the double increase is $161.
Now, let's find the single increase that would result in the same final price of $161.
Let the single increase be x%.
Using the formula for calculating a percentage increase, we can write:
$100 + x% of $100 = $161.
Simplifying this equation, we have:
$100 + 0.01x * $100 = $161.
Dividing both sides by $100, we get:
1 + 0.01x = 1.61.
Subtracting 1 from both sides, we have:
0.01x = 0.61.
Dividing both sides by 0.01, we get:
x = 61.
Therefore, the equivalent single increase is 61%.
So, the correct answer is E) 61%.