PlayTime Deposit Amount (Default) : 50 (RP)
Silver multiplier : 2
Gold multiplier : 3

When I added myself in both of group I will get 100 rp instead of getting 200 rp , My question is how to set the rank with a higher multiplier to work instead of a rank with a less multiplier?

If you give multiple permissions, the multiplier will only hit the first multiplier setup at the top of the config.

If you want to fix it set your highest tier rank at the top of you're config and the lower tiers at the bottom..