Answer:
.= 157
Explanation:
There are three clock summing up to 21
One clock=21/3
One clock= 7
There are three calculator summing up to 30
One calculator= 30/3
One calculator= 10
There are three light bulb summing up to 15
One light bulb =15/3
One light bulb= 5
So the problem expression is
Clock +calculator *3bulb
= Clock +(calculator*3bulb)
= 7+(10*3(5))
= 7 +(10*15)
= 7 + 150
.= 157