Question

help plzzzz I don't knw how to solve this

Answer 1

so profit present is 20%

Answer 2

Cost of 5 pens = S.P of 4 pens
5 C.P = 4 S.P
C.P/S.P = 4/5
C.P:S.P = 4:5
4(C.P)-------5(S.P)
P = 1
P% = 1/4 * 100 = 25%

Hope it helps.