Lovely algebra.
Given that Jack scored a number that is 17 more than Yazid's number,
1) Jack = x + 17
So we know yazid has 17 less than jack so we minus 17 from jack's equation. (x + 17) - 17 = x
2) Yazid = x
It is also given that Susan scored twice of Yazid's score therefore we can multiply Yazid's equation.
3) Susan = 2(x)
= 2x
Finally, it tells us that everyone's score added up is 161 therefore we can write the whole equation like this:
4) (x+17)+(x)+(2x) = 161
Now simplify
5) 4x + 17 = 161
Solve x by subtracting 17 from both sides.
6) 4x = 161-17
4x = 144
So x= 144/4
X=36
Now remember, Jack's equation was (x+17) so we are now able to substitute x into the equation. Since we found x = 36,
Jack = (36 + 17)
Which equals to 53.
So jack's score was 53!
