Answer:
Jack: 36
Bonus: Yazid: 53 and Susan: 72
Explanation:
Let J, Y, and K stand for Jack, Yazin, Susan's scores.
We are told that:
J = Y + 17 [Jack scored 17 marks more than Yazid]
S = 2Y [Susan scored twice Yazid's score]
J + Y + S = 161 [total score is 161]
Substitute the first two expressions into the last equation:
J + Y + S = 161
(Y+17) + Y + (2Y) = 161
4Y = 144
Y = 36
Use Y = 36 to find the other scores:
J = Y + 17
J = 36 + 17
J = 53
S = 2Y
S = 2*(36)
S = 72
CHECK:
Does 36+53+72 = 161?
YES