)alex and lara have $21.00 each to spend at a book fair, where all students receive a 35% discount. they both want to purchase a copy of the same book, which normally sells for $28.50 plus 10% sales tax. to check if he has enough to purchase the book, alex takes 35% of $28.50 and subtracts that amount from the normal price. he takes 10% of the discounted selling price and adds it back to find the purchase amount. lara takes 65% of the normal purchase price and then computes 110% of the reduced price. what is the final price?

You take the discount first. Alex is completely right. Laura is if and only if that 110% is really just 10%.  So I'll use Alex's method because it is for certain correct.

28.5*35/100 = 9.975 (which is the amount of the discount)

28.5 - 9.975 = 18.525 (which is the amount paid with the discount factored in.)

Now you take 10% of this amount and add it on which gives 18.525 * 10/100=1.825 which is the amount of the tax.

Add this on to the selling price 18.525 + 1.825 = 20.3775 and now is the time to do your rounding.

The cash register will ring up 20.38 which is just under $21.00

$20.38

i get you, what you should do is think of the positive things that would come out of it. it will make yours parents proud and raise your grade. you should always try and if you can't focus tell the teacher.