Question

Brad wants to buy flowers for his friend with $15. The daisies are $1 each and the roses are $3 each. He buys 3 more daisies than roses how much did the roses cost?

Answer 1

d + 3r = 15
d = r + 3

r + 3 + 3r = 15
4r + 3 = 15
4r = 15 - 3
4r = 12
r = 12/4
r = 3 ....he bought 3 roses, at $ 3 per rose = $ 9 <==

d = r + 3
d = 3 + 3
d = 6....he bought 6 daisies, at $ 1 per daisy = $ 6

Answer 2

Brad wants to buy flowers for his friend with $15. The daisies are $1 each and the roses are $3 each. He buys 3 more daisies than roses how much did the roses cost?
-daisies=x- -roses=y-

x+y=15

the sentence how he buys 3 more daisies than roses so...
(y=x-3)
you then plug in the value of y in the equation to have only one variable...
x+ 3(x-3)=15
you then multiply 3 to the parenthesis...
x+3x-9=15
then add 9 on both sides...
4x=24
and then divide 4 on both sides...
x=6

if you plug the value of x(daisies) in the equation...
6+y=15
you subtract 6 on both sides and get...
y=9

you can also get the answer by solving for y with x...
y=3(x-3)
(x=6)
plug in x...
y=3(6-3)
y=3(3)
y=9
Answer: the roses cost $9