What do you mean ?? about numbers

I am just guessing.

so just take - a produced in 15 min
b produced in c Hrs

hence, c hrs into 60c min

eqn becomes - a-------15
b-------60c
Its easier to take c as 1
so if a is 5 and multiplied by 3 gives 15 (5*3= 15)

therefore, b * 3= 60
b= 20

a=5, c=1, b=20 for completing an equation and moreover any other value taken for a,b,c would be a multiple of 5,1,20 resp.

b = 4a, so
4a , 3ac => 4, 3c
so the two quantities have different result for smaller c and larger c,

I'm wondering if this is a misprint. I have the text book and I've noticed a number of misprints that I had to check with other sources. I'd be wary though. Its far more likely that there is some subtle detail we are missing. I still don't understand this question. The explanation on this site is copied from the textbook and I don't see how they're getting "A" as the answer. I can pick numbers that make "B" the answer as well so I'm unsure how they are rationalizing it. Please someone help

The machine produces 1 bolt (a) in 15 min. Thus, it produces 4 bolts (b) in 1 hour (c) (not in minutes).
Option A: 4
Option B: 3*1*1 = 3
So option A is greater.

After reading the comments I noticed that, many people are converting c from hours to minutes. That is not necessary to do here. Unless and until it is stated in the question that give your answer in bolts produced per minute, then only we need to convert. Since, in this question nothing like that is stated, just substitute the value of c and a as is.

okay so firstly never assume anything is an integer unless clearly implied or explicitly stated. In this case, C is not necessarily an integer you can say 0.5 hours also.

here is an easy method to solve algebraically without any doubts:
b bolts will be produced in 60c minutes and b bolts will also be produced in 15b/a minutes so 60c = 15b/a b=4ac 4ac > 3ac since ac is positive. answer A

perfect

You are always safe to pick up any random number that you want in case of any algebric equation to avoid. I do not think there is any issue as you mentioned. COuld you be more specific, please?

I have done this algebraically,

a bolts in 15 min --- (i)

b bolts in c hours
=> b bolts in 60c min
=> b/60c bolts in 1 min
=> 15b/60c bolts in 15 min ---(ii)

number of bolts must be same in 15 minutes
So, a=15b/60c
=> a=b/4c
=> b=4ac which is term A
term B = 3ac

Hence A>B. Option (A)