Percentage!!

1)
In a sale, the selling price of a refrigerator is $1150 less than the marked price. If the discount percentage is 23%, find the selling price of the refrigerator.

Ans:
Marked price: $1150÷23%=$5xxx
Selling price: $5xxx-$1150= $3xxx

2)
There were 1200 students in a school last year,in which 56% were girls. This year, the total number of students in the school remains unchanged, but there are 30 more boys. Find the percentage of boys in the school this year.



Ans:
last year, boys : 1200x(100%-56%) = 5xx
this year, boys : (5xx+30)÷1200x100% = 4x.x%

3)
Two shops are selling the same model of calculator. In shop A, the marked price of the calculator is $150 and the shop offers a 20% off discount.In shop B, the marked price of the calculator is $160 and it is now $35 less.Which shop would you go to buy the calculator? Explain your answer.

Ans:
In shop A : $150
In shop B : $150x(1-20%) = $1xx
In shop C : $160-$35 = $1xx

∴ I would go shop x to buy the calculator.