All 'em presents cost how much?

[Rudi]

This basic problem should warm up your mental skills before you run out an buy them presents...

For sum , it shouldn't take longer than a minute ...

Five presents were bought for Christmas
The red and purple presents together cost $31,
The purple and blue presents together cost $20,
The blue and gold presents together cost $27,
The gold and green presents together cost $38,
The green and red presents together cost $34

What is the total cost of all five presents?

[HansV]

Answer:

Spoiler

$75

Explanation:

Spoiler

The sum of the five amounts is $150; each color is counted exactly twice.

[Rudi]

That's what I go too

Spoiler

I caught myself wanting to solve it via some algebraic process; but then I thought, hang on, if each item is listed twice, just add all prices and divide by 2.