Answer: They would need 15 days
Step-by-step explanation:
The data is:
Company A produce 100 CPUs in 3 days, so the rate per day is:
Ra = 100/3 CPUs per day: 33.33 CPUs per day.
Company B produce 150 CPUs in 4 days, then it produces:
Rb = 150/4 = 37.5 CPUs per day.
Then, if both companies work toggeter, they produce
Ra + Rb = 33.33 + 37.5 CPUs per day = 70.83 CPUs per day.
We want to know the number X of days needed to make 1000 CPUs, then we need to solve:
70.83*X = 1000
X = 1000/70.83 = 14.11 days, we could round it up to 15 days if we want to have a whole number.