A motorboat travels 9 miles downstream (with the current) in 30 minutes. The return trip upstream (against the current) takes 90 minutes. Which system of equations can be used to find x , the speed of the boat in miles per hour, and y , the speed of the current in miles per hour? Recall the formula d is equal to rt .
Answer
A
1 point 5 is equal to 9 times x minus y 0 point 5 is equal to 9 times x plus y
B
9 is equal to 0 point 5 times x minus y 9 is equal to 1 point 5 times x plus y
C
0 point 5 is equal to 9 times open paren x minus y close paren 1 point 5 is equal to 9 times x plus y
D
9 is equal to 1 point 5 times open paren x minus y close paren 9 is equal to 0 point 5 times x plus y