Using longer sentences.
What we know
>1 machine produces 1 toy every 3 mins
> hence 1 machine makes 1/3 or a toy in 1 min
> hence 1 machine will make X Toys @ 1/3 *60
> hence 1 machine will make 20 toys in 60 mins or 1hr
> 40% of the machines are to be replaced
>>hence 60% of the machine will work at the same rate
Let's solve
1. Let's say 10 machines are there
> 10 machines * 20 toys per machine = 200 toys in 60 mins
of 1/3. THE ORIGINAL PRODUCTION QUANTITY
2. Since 40% are replaced
PART 1. NEW MACHINE output
>((40/100)*10*) = number of new machines
> 4 new machines
> 4 NM make 1 toy every 2 mins individually
> hence 1 NM work @ 1/2 toy every min
> hence 1 NM 1/2 toy * 60 mins
> hence 1 NM 30 toys in 1 hour
> hence 4 NM make 30 *4 in 1 hour
> Total NM output = 120 in 1 hour
PART 2. Original Machine output
> 6 machines * 20 toys per 1 hour
> hence OM make 6*20 per 1 hour
> hence OM makes 120 per 1 hour
PART 3.
NM + OM = 240
PART 4.
> Change/Original * 100%
> ((240-200)/200)* 100%
> hence (40/200)*100
> hence 20%