Question 1084592
Make the number of calls received on the first evening = x
First evening = x
Second evening = x - 6
Third evening = 4(x)
Add them all together
x + (x - 6) + 4x = 108
Remove brackets
x + x - 6 + 4x = 108
Collect like terms
6x = 108 + 6
6x = 114
x = 19
First evening = 19 calls  (x)
Second evening = 13 calls  (x - 6)
Third evening = 76 calls (4x)
Hope this helps :-)