A service station has 2 kinds of oil, one selling for $1.27/litre and the other for$1.18/litre. How many litres of each must be used to make 90 litres of a mixture that can be sold for $1.24/litre? 2. Originally Posted by princess_anna57 Please help! A service station has 2 kinds of oil, one selling for$1.27/litre and the other for $1.18/litre. How many litres of each must be used to make 90 litres of a mixture that can be sold for$1.24/litre?
Let x be the number of litres of the 1.27 oil, then there are 90-x litres of
the other. The price of the mixture will be:

(1.27*x+1.18*(90-x))/90 dollars per litre.

You will need to find x such that the price of the mixture will be 1.24.

RonL

3. Originally Posted by princess_anna57
A service station has 2 kinds of oil, one selling for $1.27/litre and the other for$1.18/litre. How many litres of each must be used to make 90 litres of a mixture that can be sold for $1.24/litre? Hello, let x be the amount of oil which is sold for$1.27
then (90-x) is the amount of oil which is sold for $1.18. Now you can set up the equation:$\displaystyle x \cdot 1.27 - (90-x) \cdot 1.18 = 90 \cdot 1.24$. Expand the bracket and collect like terms :$\displaystyle x \cdot 1.27 - x \cdot 1.18 = 90 \cdot 1.24 - 90 \cdot 1.18\displaystyle x \cdot 0.09 = 5.4$. Divide both sides of the equation by 0.09 and you'll get:$\displaystyle x = 60$That means: Take 60 ltrs of the$1.27-oil and 30 ltrs of the $1.18-oil to get the mixture which you can sell for$1.24