Gressel the Goblin is making an inventory of Darklord Ganondorf’s treasure horde following a raid by some violent fellow named link. The horde now contains only 2150 gems (as in $). Gressel notices that there were twice as many green-gems (worth 1) as blue-gems (worth 5) and 13 fewer blue gems than red-gems (worth 20). How many red, blue and green gems are there remaining in the horde? ​

Explanation:

Let  the   number of blue  gems  =  B

Let  the number of   green gems  = 2B

Let  the  number of red  gems = B + 13

So

5B  + 1*2B  + 20 ( B + 13)  =  2150   simplify

27B + 260 =  2150

27B  = 2150 - 260

27B  = 1890

B =  1890 / 27  =  70   blue gems

2*70  =  140  green gems

70 + 13  =  83  red gems

web 2 calc site

Let the number of blue gems be B.

Let the number of green gems be 2B.

Let the number of red gems be B + 13.

So,

5B + 1 × 2B + 20 (B + 13) = 2150

On simplifying, we get

27B + 260 = 2150

27B = 2150 - 260

27B = 1890

B = 1890/27 = 70 blue gems.

And, 2 × 70 = 140 green gems.

70 + 13 = 83 red gems.