Answer:
9.6
Step-by-step explanation:
By setting up a system of equations we can easily solve this problem. Let's denote Jane's working hours with x and Jack's working hours with y. Since they don't want to work more than 65 hours, the first equation is x+y=65. The second equation is 14x+7y=770. By solving this system of equation

, we find that y=20 hours, which is Jack's maximum working hours.
Answer:
3.93700787402, almost 4
Step-by-step explanation:
10 ÷ 2.54
3 × 2.50 = 7.50
3 × 0.04 = 0.12
7.50 + 0.12 = 7.65
7.65 + 2.54 = 10.19
The precise number is use calculator.