Can u help me with my math assignment 4 school?

Question

i need to know HOW to do the problems pleasee!!

heres the Q: bob bought salads at $2.75 each and cartons of milk at $0.80 each. the total cost was $16.15. how much of each did he buy?

and

a rectangular garden is 45 ft. long and the perimeter is 150 ft. Rows of plants are planted 3 ft apart. find the area of the garden.

and..

u spend $13 to rent 5 movies. new releases cost $3 and regular movies rent cost $2, how many regular movies did u rent? how many releases did u rent?

IF U CAN ANSWER ANY THAT WOULD BE A HELP. but i need to know the formula/ work on how to do it :) :) thank uuuuuu!

Answer 1

For the last one, you use the equations

N is new releases, R is regular

N + R = 5

3N + 2R = 13

You solve one variable first, so using the first equation is the easiest.

I'll solve for R first.

So using the first equation R = 5 - N

Substitute that into the second equation

3N + 2(5 - N) = 13

Simplify 3N + 10 - 2N = 13

              N + 10 = 13

         So N = 3

Plug that back into either of the equations

Using the first one 3 + R = 5

So R = 2

For the other two I think more information is needed to solve them.