John and his friends are going out for pizza for lunch. They split one pizza and 3 drinks. The pizza cost $12.00. They spent a total of $16.95. Find the cost of one large drink.
--pizza=P-- --drinks=D-- --john and his friends=J--
they split one pizza and 3 drinks...
(J=P+3D)
the pizza cost $12.00...
(P=$12)
since you know the value of P you plug it in...
(J=$12+3D)
they spent a total of $16.95...
J=$16.95
since you know the value of J you plug it in...
$16.95=$12+3D
and since you have only one unknown variable you can now solve by subtracting $12 on both sides...
$4.95=3D
then you divide 3 on both sides to keep the variable by itself...
$1.65=1D
and you end finding the cost of one drink
1D=$1.65 (D=$1.65)