Let p be the prize of a pen and m the prize of a mechanical pencils. If you buy six pens and one mechanical pencil, you spend 6p+m. We know that this equals 9, because you get 1$ change from a 10$ bill.
Similarly, if you buy four pens and two mechanical pencils, you spend 4p+2m, which is 8$, because now you get a $2 change. Put these equation together in a system:
Now, if you multiply the first equation by 2, the system becomes
Subtract the second equation from the first:
Plug this value into the first equation to get
Let Sara weight =x+25
amber wiegh =x
x+25+x=205
x= 90
Sara weight is 90+25= 115
Answer:
24.75 = 3*4.50 + x*4.50
x= 2.5 pounds of Granny Smith apples
Step-by-step explanation:
Gala apples = 3 lbs
Granny apples = x lbs
They cost 4.50 a pound
Total cost = 24.75
Total cost = gala apples * cost per pound + granny apples * cost per pound
Substitute in what we know
24.75 = 3*4.50 + x*4.50
24.75 = 13.50 + 4.5x
Subtract 13.50 from each side
24.75-13.50 = 13.50-13.50 + 4.5x
11.25 = 4.5x
Divide by 4.50 on each side
11.25/4.5 = 4.5x/4.5
2.5 =x
9x+14x+4x+90 = 360
27x = 270
x = 10
<F = 14x = 14(10) = 140
