Luis has a $10 bill and three $5 bills. he spends $12.75 on the entrance fee to an amusement park and $8.50 on snacks. how much money doe she have left

She has a total of $3.75 left

Step-by-step explanation:

Step 1

Express the amount of money Luis had in the beginning as follows;

A=E+R

where;

A=initial amount he had at the beginning

E=total expenditure

R=total remainder after spending

In our case;

A=(1×10)+(3×5)=$25

E=Amount spent at amusement park+amount spent on snacks

E=(12.75+8.50)=$21.25

R=unknown=r

Step 2

Substitute the values in the expression and solve for A;

25=21.25+r

r=25-21.25=3.75

r=3.75

She has a total of $3.75 left

d. $180

step-by-step explanation:

if the dimensions of the room is 9ft by 12 ft, we have the area of the floor as,

so the area of the floor is 108 square feet, converting that into square yards we get,

the cost of carpet is $15 per square yard, therefore the cost of carpet for 12 square yards is,

hence, the cost of carpet is $180.

assuming the dimensions of the room be,

15 ft by 12 ft

so, the area of the floor of that room is,

we can convert 180 square feet into square yards, we know that,

1 sq ft = 0.111 sq yard

so, 180 square feet is,

so the area of floor is 20 square yards.

now, the cost of carpet is 15 dollars per square yard, therefore the cost of carpet for 20 square yards is,

so, it will cost $300.