How much antifreeze 25% antifreeze and 50% antifreeze should be combined to give 40 gallon of 30% antifreeze?

32 gallons of 25 % antifreeze should be combined with 8 gallons of 50 % antifreeze to get 40 gallon of 30% antifreeze

From given,

Final mixture is 40 gallon

Let "x" be the gallon of 25 % antifreeze

Then, (40 - x) is the gallon of 50 % antifreeze

Therefore, according to question,

"x" gallons of 25 % antifreeze should be combined with (40 - x) gallons of 50 % antifreeze to get 40 gallon of 30% antifreeze

25 % of x + 50 % of (40 - x) = 30 % of 40

Solve for "x"

Thus, 32 gallons of 25 % antifreeze is used

Then, (40 - x) = (40 - 32) = 8

Thus 8 gallons of 50 % antifreeze is used

The principal amount is $10160

Step-by-step explanation:

Given; Simple interest, I = 7620

Rate, R = 6.25

Time, T = 12

Principal, P =?

The formula for simple interest, I is;

Making P the subject of formula;

Therefore, the principal amount is $10160