A teacher asked his three students, Tom Helen and Sandy to complete 200 exercises the ratio of the exercises completed by Helen to the exercises completed by Sandy is 3:3:4. Tom receives 5 points for each completed exercise. Sandy receives 8 points for each exercise. If the three students altogether receive 1240 points, how many points does Helen receive for a completed exercise?

x + 107

step-by-step explanation:

let's say that the number he had before the mistake was x. then, he will have 107 dollars more than this, so the answer is x + 107.

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.