what is 15% of $9.10

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A percentage can be converted to a fraction or decimal. A dollar amount is just a decimal number with a unit (dollars) attached to it. You figure the operation on decimal numbers in the usual way. Then attach the unit as required.

__Examples__40% of $15 40% of $15 = $(0.40*15) = $6.00 $15 with 40% taken off $15 - 40% of $15 = $15*(1 - 0.40) = $15*0.60 = $(15*0.60) = $9.00 (Of course, you can use the result of the first example to compute $15 - 40% of $15 = $15 - $6 = $9 What percentage of $15 is $3? $3/$15*100% = (3/15)*100% = (300/15)% = 20% Often, you want to figure 15% or 20% of a number using mental arithmetic. Remember that 10% = 1/10, and that dividing by 10 is just a shift of the decimal point.**10% of $15.00**, for example, is**$1.50**. Now, if you want 20%, you just double this number. 20% of $15.00 = (2)*($1.50) = $3.00. On the other hand, if you want 15%, you can cut the 10% value in half to get 5%, then add that. 15% of $15.00 = 10%*$15.00 + (1/2)*10%*$15.00 = $1.50 + ($1.50)/2 = $1.50 + $0.75 = $2.25Convert the percentage to a decimal and multiply by the dollar amount.

__Example__**20% of $4.50**= 0.20*$4.50 (convert the % to decimal by moving the decimal point left 2 places, drop the %) = $0.9000 (20*450 = 9000. There are 2+2=4 decimal digits.)**= $0.90**(we only keep 2 decimal digits for dollar amounts)