a)Since they are all identical pens, cost of each pen= 3/5÷6=1/10

Each pen will cost her 1/10 of her money

b) First find the cost of 1 pencil as a fraction of the amount of money she has.
The she bought a total of 9 pens and 10 pencils with all of her money.

Cost of a pen=1/10
Total cost of 9 pens=9/10
Remaining amount spent on 10 pencils= 1/10 of her total amount
Cost of each pencil=1/10÷10=1/100

Since the cost we found is as a fraction of the total amount of money she has, we know that she can buy 100 pencils if she spent all her money on pencils.

For every 14 pencils you get 1 pencil for free, so how many sets of 14 pencils are there in 100?

Number of sets of 14 pencils= 100÷14=7 sets of 14 pencils with 2 pencils remaining.

For each set you get 1 pencil so you get a total of 7 pencils for free.

So the total number of pencils = total number of pencils she gets if she spends all her money on pencils + the total number of pencils that she gets for free if she spents all her money on pencils= 100+7=107