Question

Thomas took three 100-point quizzes, and the mean score for the three quizzes was 87 points. If the highest score is taken away, the mean of the remaining two scores would be 83.5 points. If the lowest score is taken away, the mean of the remaining two scores would be 89 points. What is the highest score?

Answer 1

The highest score is 94.

Explanation:

Let the highest score be denoted by, A, the lowest score be, B and the middle score be X.

Then,

A + X + B = 87 × 3 = 261 ...(i)

X + B = 83.5 × 2 = 167 ...(ii)

⇒ B = 167 - X ...(iii)

A + X = 89 × 2 = 178 ...(iv)

⇒ A = 178 - X ...(v)

Substitute (iii) and (v) in (i) and solve for X as follows:

A + X + B = 261

178 - X + X + 167 - X = 261

345 - X = 261

X = 84

Substitute the value of X in (iii) and solve for B as follows:

B = 167 - X

= 167 - 84

= 83

Substitute the value of X in (v) and solve for A as follows:

A = 178 - X

= 178 - 84

= 94

Thus, the highest score is 94.