Question

1. 20 pens cost 300 and 50 pens cost 750

a. is the cost of pens directly proportional to the number of pens
b. calculate the cost of buying 80 pens
ii.) calculate the number of pens if the cost is 1335​

Answer 1

A) yes.
Because , 20x(x represent money$ for 1 pen)
20*15=300
50*15=750

B)

20 pens =300$

So,
300/20= 15$
1 pen = 15$

On the other hand,
50 pens= 750
So,
750/50=15$
1 pen= 15$

So,80 pen ,
80x
80*15=1200$

ii) x pens= 1335
So we know 15$ for one pen!
15 pens=1335

Pens= 1335/15
89 = pens