Carl

carl bought 19 apples of 2 differnet varieties to make a pie. The totla cost of apples was $5.10. Granny Smith apples cost $0.25 each and gala apples cost $0.30 each. How many of each type of apple did Carl buy?

Let the number of Granny Smith=S

Let the number of Gala=G

G + S =19

.25S + .30G=5.10

Swap equation 1 with equation 2:

{G+S = 19 | (equation 1)

0.3 G+0.25 S = 5.1 | (equation 2)

Subtract 0.3 × (equation 1) from equation 2:

{G+S = 19 | (equation 1)

0 G-0.05 S = -0.6 | (equation 2)

Divide equation 2 by -1.:

{G+S = 19 | (equation 1)

0 G+0.05 S = 0.6 | (equation 2)

Divide equation 2 by 0.05:

{G+S = 19 | (equation 1)

0. G+S = 12. | (equation 2)

Subtract equation 2 from equation 1:

{G+0 S = 7. | (equation 1)

0 G+S = 12. | (equation 2)

Collect results:

Answer: |G = 7        and          S=12

.25(12) +.3(7) = 5.1

So, carl bought 12 granny smith and 7 gala. I used guess and check, though. Could someone reply the method to use? 

I gotcha bruh

Let x = the number of Grannies

Let y = the number of gala

5.1=.25x+.3y

Solve for a variable, either one

I will do both

y=(5.1-.25x)/.3

or

x=(5.1-.3y)/.25

19=x+y

Then substitute

19=(5.1-.25x)/.3+x

or 

19=(5.1-.3y)/.25+y

5.7=5.1-.25x+.3x

.6=.05X

.6/.05 = 12 = X

or

4.75=5.1-.3y+.25y

-.35=-.05y

.35/.05 = 7 = y

Granny = 12

Gala = 7

Elimination Plz, thank you tho