Question

The numbers a,b,c are the three digit number which satisfy 49a+7b+c=286.then the value of 100a+10b+c is?

Answer 1

See below.

Explanation:

If `abc_7 = 286_(10)` then `a=5,b=5,c=6` because

`556_7 = 286_10`

`286 equiv a mod 7`

`(286-c)/7 equiv b mod 7`

`((286-c)/7 -b)/7 equiv a mod 7`