Question

Antoine and Tess have a disagreement over how to compute a 15% gratuity on $46.00. Tess says, “It is easy to find 10% of 46 by moving the decimal point one place to the left to get $4.60. Do that twice. Then add the two amounts to get $4.60 + $4.60 = $9.20 for the 15% gratuity.” How should Antoine respond to Tess’s method?

Answer 1

if 10% = 4.60 then by adding 4.60 to 4.60 he doubled the percent 10% +10% = 20%

 he should have taken half of the 4.60 for the 5% since 5 is half of 10

half of 4.60 = 2.30

 then add them 4.60 +2.30 = 6.90 = 15%