Me on this question, also give explanation .

15% of $70 is 10.5.

This is because (70/100) times (15/100) gives us 0.105, times by 100 is 10.5

Adding $10.50 to $70 gives us $80.50. From the options in your picture, the second one down ($80) is the closest. 

Hey there,
100 % = $ 70
1% = $ 70 / 100
      = $0.70
15% = $10.50
Total = $70 + $10.50
         = $80.50

Hope this helps :))

~Top

The correct answer is c