In a school in which 40% of the enrolled students are boys, 80% of the boys are present on a certain day. If 1152 boys are present, the total school enrollment is _______.
The Usual Method
Let the total enrollment be ‘x’.
Hence total number of boys = 40% of x = 0.4x.
Total number of boys present = 80% of boys =
Also total number of boys present = 1152
Estimated Time to arrive at the answer = 60 seconds.
We know that 80% of the boys present out of the total 40% boys make 0.32x = 1152.
We also know that 1/3 = 0.33. Hence we can approximate 0.32 as 0.33 and so 1152 is approximately 1/3 of the total enrollment. Hence total enrollment = (+).
(Note: The ‘+’ sign indicates that the answer is slightly greater than 3300).
From the options we see that 3600 is the only one closest to 3300 and greater than that. Hence, 3600 is the answer.
Estimated Time to arrive at the answer = 15 seconds.