In a box there are many one-euro, two-euro, and five-euro coins. A dispencer draws coins out of the box - one at a time, and stops when three identical coins are taken out. What is the largest possible amount that can be withdrawn?
The answer is 21, please explain why

We want the biggest amount, so here goes:

1. one-euro

2. one-euro

3. two-euro     (he can't pick a one-euro here, otherwise he's done!)

4. two-euro

5. five-euro (he can't pick a two-euro here, otherwise he's done!)

6. five-euro

7. five-euro

1+1+2+2+5+5+5 = 21

(23*2)-12=x     x=34

step-by-step explanation:

m∠a is 90°

m∠b is 40°