Troller, Ver 2.0

Number Theory Level pending

The sequel to the popular problem Troller. It is advised you solve the other problem first before attempting this one.

Another woman was tired of people asking her age, so she composed a riddle to hide her real age.

Seventy-two raised to the power of fifty-three

Divide that by seven and the remainder will be

As much as a hundredth of my age times four

Plus a hundredth of my age and the square root of four.

How old is the woman?


The answer is 40.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Victor Loh
May 9, 2016

Note that 7 2 53 2 53 = ( 2 3 ) 17 × 4 4 ( m o d 7 ) . 72^{53} \equiv 2^{53} = (2^3)^{17} \times 4 \equiv 4 \pmod 7.

Let the woman's age be 100 x 100x . Then 4 = 4 x + x + 2 100 x = 40 4=4x+x+2 \implies 100x=\boxed{40} . We are done.

Wonderful solution.

Log in to reply

Thanks @Jerry Han Jia Tao !

Victor Loh - 5 years ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...