Let the cost of one pen be x and one pencil be y.

Given that, the cost of two pens are 30 Rs.

Therefore,

2x = 30
x = 30/2
x = 15

Thus, the cost of one pen is 15 Rs.

Given that, Ann bought 2 pens and 5 pencils and the total cost is 80 Rs.

Therefore,

2x + 5y = 80

Substiute x = 15 in the equation,

2(15) + 5y = 80
30 + 5y = 80
5y = 80 - 30
5y = 50
y = 50/5
y = 10

Thus, the cost of one pencil is 10 Rs.

Therefore, cost of one pen is 15 Rs. and cost of one pencil is 10 Rs.