According to Hooke's Law, the force required to hold the spring stretched x m beyond its natural length is given by f(x) = kx,
where k is the spring constant.
Suppose that 24 J of work is needed to stretch a spring from 12 cm to 16 cm and another 40 J is needed to stretch it from 16 cm to 20 cm. Find the exact value of k, in N/m.

Acompany manufactures three types of cabinets. it makes 110 cabinets each week. in the first week, the sum of the number of type-1 cabinets and twice the number of type-2 cabinets produced was 10 more than the number of type-3 cabinets produced. the next week, the number of type-1 cabinets produced was three times more than in the first week, no type-2 cabinets were produced, and the number of type-3 cabinets produced was the same as in the previous week.