[Question]: Dina has twice as many dolls as Ivy. 2/3 of Ivy's dolls are collectors editions. If Ivy has 20 collectors edition dolls, how many dolls does Dina have?
[Answer]: Ivy has 20 / 2 * 3 = 30 dolls. Dina has 30 * 2 = 60 dolls.
So the answer is 60.

[Question]: John decides to buy some birds. He got 50 dollars from each of his 4 grandparents. If each bird costs $20, how many wings did all the birds have?
[Answer]: He got 4 * 50 = $200. That means he was able to buy 200 / 20 = 10 birds. Since each bird has 2 wings he got 10 * 2 = 20 wings.
So the answer is 20.

[Question]: Robert, a sales agent, earns a basic salary of $1250 per month and, 10% commission on his monthly sales. Last month, his total sales were $23600. He allocated 20% of his total earnings to savings and the rest of the money to his monthly expenses. How much were his monthly expenses last month?
[Answer]:
Robert earned a commission of $23600 x 10 / 100 = $2360. So, he earned a total of $1250 + $2360 = $3610. And, he saved $3610 x 20 / 100 = $722. Therefore, his total expenses last month was $3610 - $722 = $2888.
So the answer is 2888.