How would you solve this?

Question

If a motorist asks for ten dollars worh of gasoline and gasoline is selling at $1.29 per gallon, find the number of gallons she will recive, to the nerest tenth of a gallon

Answer 1

10/1.29 = number of gallons

Answer 2

This is a very simple equation so I'm assuming that the method escapes you. There are a couple way to look at this but I'd look at the ratio first. The clue here is the word per which implies a ratio. So we could say

$1.29 is to 1 gallon as $10 is to X gallons. or $1.29:1 - 10:X. And since ratios are really division, you take the units which in this case is 1 and divide by the price. 1 / $1.29 = 0.7752. Then multiply by the new price, 10 and you get 0.7752*10 = 7.752 gallons    

OR it's probably easier to cross multiply if you've learned that yet. The same ratio above can be shown as

1.29 over 1 equals 10 over y   or  1.29/1 = 10/y

cross multiply means you take the dividend of each fraction (ratio) and multiply it by the divisor or the other, then solve normally, so the above becomes

1*10 = 1.29*y   or  10 = 1.29*y

divide both sides by 1.29 to isolate the y and you get

10/1.29 = y    or  y = 7.752 gallons.

Now what if $1.29 bought 2 gallons? Did you learn enough to do the next one yourself? If not, ask your teacher for help before you get in too deep.            Good Luck

Answer 3

The equation would be Y= 10/1.29 Which rounded is 7.6