Question

Meshia spent $14.50 on a total of 10 items. She bought soft drinks for $1.25 each and popcorn for $1.75 each. How many soft drinks did she buy?

Answer 1

i got these worked down to one formula:

amount @ y = t(z-x)/(y-x)

amount @ 1.25 = (14.50-10(1.75))/(1.25-1.75) perhaps?

Answer 2

if i did it right; I get 6 at 1.25; gotta double check tho

Answer 3

ok.thanks

Answer 4

6(1.25) + 4(1.75) = 14.50
7.50 + 7.00 = 14.50 .. looks good to me :)

Answer 5

right

Answer 6

actually 2 formulas

amount @ y = t(z-x)/(y-x); which this doesnt call for

and

amount @ y = (z-tx)/(y-x) ; which this one uses

Answer 7

thanks

Answer 8

to work out the details tho; you wanna create 2 equations

a + b = t (for total)

ax + by = z (where z is the amount given), this one we need

now we can use elimination on these


a + b = t <-- multiply by -x
ax + by = z



-ax -bx = -tx
ax + by = z
-------------- ; and add them up
b(y-x) = z - tx ; and solve for b

b = (z-tx)/(y-x) ...