Question

Tan had 40 more yellow files than green files. After he sold 20 yellow files and green files, there were twice as many yellow files as green files left. w many green files did Mr Tan have at first?​

Answer 1

• Tan had 60 green files

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Let the number of green files be x.

Tan had 40 more yellow files than green files, which means he had x + 40 yellow files.

After selling 20 yellow and green files, Tan had x - 20 green files and (x + 40) - 20 yellow files.

We also know that after selling 20 files, there were twice as many yellow files as green files left.

So we can set up the equation:

• 2(x - 20) = (x + 40) - 20

Simplifying this equation:

• 2x - 40 = x + 20
• x = 60