Question

Hadi earned $120.00 from his job yesterday. Today he expects to earn 15% less than yesterday and tomorrow he expects to earn 15% more than today. What is the combined amount Hadi expects to earn for three days

Answer 1

Yesterday Hadi earned: $120

Today he will earn: $120*85% = $102
(You times the amount yesterday by 85% because you want to find the 15% less of 100% of the amount he's earned yesterday. Therefore, to find 15% less than yesterday you multiply it by 85% (100% - 15%) )

Tomorrow he will earn: $102*115% = $117.30
(Same thing here, however you are finding 15% more than 100% today. Therefore, you multiply the amount he earned today it by 115% (100% + 15%) )

To find the amount he earns for the three days you must add the amount earned of yesterday, today and tomorrow earned from the working above.

Therefore, Hadi expects to earn: 
Yesterday + Today + Tomorrow = 120 + 102 + 117.30 = $339.3

Answer 2

Yesterday Hadi earned: $120

Today he will earn: $120*85% = $102
(You times the amount yesterday by 85% because you want to find the 15% less of 100% of the amount he's earned yesterday. Therefore, to find 15% less than yesterday you multiply it by 85% (100% - 15%) )

Tomorrow he will earn: $102*115% = $117.30
(Same thing here, however you are finding 15% more than 100% today. Therefore, you multiply the amount he earned today it by 115% (100% + 15%) )

To find the amount he earns for the three days you must add the amount earned of yesterday, today and tomorrow earned from the working above.

Therefore, Hadi expects to earn:
Yesterday + Today + Tomorrow = 120 + 102 + 117.30 = $339.3