A certain shop sells only red pens and blue pens.
A red pen sells at 100 yen each , and a blue pen sells at 120 yen each.
How many blue pens were sold last week.

(1)Last week the number of blue pens which were sold in the shop was 50% greater than that of red pens.
(2)Last week the shop recieved a total of 10,000 yen from the sale of pens.