Five numbers were written on the whiteboard as shown:
- Write down the 3 numbers that will give an average of 62. Give your answers in ascending order. (Eg 1, 2, 3)
- After Glen wrote 2-digit number on the same whiteboard, the new average of the six numbers became a whole number and a multiple of 7. What was the largest possible 2-digit number written by Glen?
(a)
Total of 3 numbers
= 3 x 62
= 186
37 + 64 + 85 = 186
The 3 numbers that will give an average of 62 = 37, 64, 85
(b)
Total of 5 numbers
= 64 + 37 + 109 + 27 + 85
= 322
Total of 6 numbers |
Average of 6 numbers |
Is it a whole number? |
322 + 99 = 421 |
421 ÷ 6 ≈ 70.2 |
No |
322 + 98 = 420 |
420 ÷ 6 = 70 |
Yes |
70 ÷ 7 = 10
70 is a multiple of 7.
Highest possible 2-digit number = 98
Answer(s): (a) 37, 64, 85; (b) 98