Word problem that i need help with

Question

One number is 77 times a first number. A third number is 100 more than the first number. If the sum of the three numbers is 721, find the numbers.

Answer 1

n = first number

77n = second number

n + 100 = third number

n + 77n + (n + 100) = 721

Can you solve for n and finish from here?

Answer 2

What we need to find is the value of A (what they are calling the first number).

A

B=77A

C=A+100

A+77A+ (A+100)=721

Put all the A's together (since they are the same)

79A+100=721

-100

79A=621

%79

A=7.86

B=7.86x77

C=7.86+100

7.86+605.22+107.86=721