x is the number of minutes spent swimming and burns 10 calories per minute swimming; it's 10x
y is the number of minutes spent biking and 7 calories per minute biking; it's 7y
He wants to burn a minimum of 600 calories; it's 10x + 7y <= 600
The time Dylan spends swimming must be no less than twice the time he spends biking; it's x >= 2y
So now you have the system of inequalities:
10x + 7y <= 600
x >= 2y
Substitute each points into the equations:
(44,25)
10(44) + 7(25) <= 600
440 +175 <= 600
615 > 600 ......................>NO
44 >= 2(25)
44 < 50 ......................>NO
(44,25) is NOT the solution of the system of equations
(46,20)
10(46) + 7(20) <= 600
460 +140 <= 600
600 <= 600 ......................>YES
46 >= 2(20)
44 >=40 ......................>YES
(46,20) is the solution of the system of equations
(37,19)
10(37) + 7(19) <= 600
370 +133 <= 600
503 <= 600 ......................>YES
37 >= 2(19)
37 < 38 ......................>NO
(37, 19) is NOT the solution of the system of equations
(52,12)
10(52) + 7(12) <= 600
520 +84 <= 600
604 > 600 ......................>NO
52 >= 2(12)
52 >=24 ......................>YES
(52, 12) is NOT the solution of the system of equations
Answer:
Inequalities:
10x + 7y <= 600
x >= 2y
Solution: (46,20)