How many ounces of pure oil should be mixed with an oil-gas solution that is 4.51% oil, to get 100 ounces of an oil-gas mixture that is 15% oil

≈ 11 ounces

Step-by-step explanation:

(This is the easiest method I can explain, there is probably a simpler one)

We can make a system of equations (x = oz. of pure oil, y = oz. of mixture):

x + y = 100 oz. -> y = 100 - x

x + 0.0451y = 0.15(100) -> x + 0.0451y = 15

Using substitution, we get that x + 0.0451(100 - x) = 15.

This is equal to x + 4.51 - 0.0451x = 15.

Subtracting both sides by 4.51 and combining like terms gets us

0.9549x = 10.49.

Dividing both sides gives us about 11 ounces.

the answer to the expression is 83

total amount to be paid = $19.5

step-by-step explanation:

given ,

original price = $25.99

discount = 25%

discount amount = 25% of original price

discount amount = 25/100   * 25.99

discount amount = $6.49

hence , the total amount to be paid = original price - discount amount

                                                            = $25.99 - $6.49

                                                            =$19.5

total amount to be paid = $19.5