Question

If Machine X can produce 1,000 bolts in 4 hours and Machine Y can produce 1,000 bolts in 5 hours, in how many hours can Machines X and Y, working together at these constant rates, produce 1,000 bolts?

• A. $3\frac{2}{9}$ hours
• B. $2\frac{2}{9}$hours
• C. $1\frac{2}{9}$ hours
• D. $3\frac{3}{4}$ hours

Answer 1

Answer: (B)

$2\frac{2}{9}$hours

Machine X can produce 100 bolts in 4 hrs.

So, it can produce $\frac{1000}{4}=250$ bolts in an hour.

Machine Y can produce 1000 bolts in 5 hrs.

So, it can produce $\frac{1000}{5}=200$ bolts in an hour.

So, together they can produce $250+200=450$ bolts in an hour.

So, they will produce $1000$ bolts in $\frac{1000}{450}=2\frac{2}{9}$ hours. Option B