It won't work long term. You might make like 10 cents per PC now with Zcoin but in a month, you would make maybe 1-2 cents a day with all 50 of those PCs. You need a GPU to mine.
this is wrong info if he has i5's
i5's cpus are doing 20h x 50 = 1000h
now he needs to give 1 core to the user so the 1000h drops to 750h
take ⅓ off for power down he drops to 500h
I am earning 150 usd a day with 350h
lots of caveats here.
first all i5's are not the same
second he may need to give 2 cores not one core
so 1000h x ½ = 500h x ⅔ = 333h which earns about 140 usd a day.
but this is a smoking hot coin and this could be very short term
and he could have shit cpus like a pentium g 4400 which earns 4h not 20 h