Troys truck has a 30 gallon gas tank and gets and average of 21 miles per gallon

The answer is 630 miles using a 30 gallons tank.

Step-by-step explanation:

Well this question is incomplete, but if we are trying to find how many miles can 30 gallons give then the answer would be 630.

Why? Well since 21 miles = 1 gallon then 630 miles = 30 gallons.

Because 21 multiplied by 30 = 630.

P.S Can I have brainliest if I am correct?

a

step-by-step explanation:

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.