The Surprising TRUTH about Harvard University Entrance Exam Nobody tells you

[@michaeledwards2251]

I recognized 6!7! = 10! from prior problems, leaving x = 15. I felt the first method was the simplest for a human, but a computer implementation should use the 2nd method. Excellent explanation!

[@superacademy247]

Thanks ✅🥰🤩

[@raghvendrasingh1289]

(x-5)! = 7! 720 = 10*9*8*7! = 10!
x = 15

[@YAWTon]

The only factorial which is divisibke by 25 but not by 11 is 10!. So, x-5=10, x=5.

[@THyperon]

If x-5=10, then x=15

[@richardl6751]

What is the surprising TRUTH?

[@shmuelzehavi4940]

The suprise itself.

[@CharlesChen-el4ot]

（x-5)! = 10! = 6!*7!
x = 15

[@walterwen2975]

x = 15

[@RylanceStreet]

6!×7!
=1x2x3x4x5x6x7!
=2x3x2x2x5x2x3x7!
=7!x2x2x2x3x3x2x5
=7!x8x9x10
=10!
(x-5)!=10!
x-5=10
x=15