The number (b) of bolts a machine can make varies directly as the time (t) it operates. it can make 6,000 bolts in 2 hours. how many can it make in 5 hours?

For this case we have a function of the form:
 b = k * t
 Where,
 k: proportionality constant.
 For this case:
 k = 6000/2
 k = 3000
 Substituting values:
 b = 3000 * t
 For t = 5 we have:
 b = 3000 * 5
 b = 15000
 
 it can make in 15000 bolts in 5 hours