An amount becomes double in 7 years on simple interest. The amount would be four times in ______ years on the same rate of simple interest.

An amount becomes double in 7 years on simple interest. The amount would be four times in ______ years on the same rate of simple interest.
साधारण ब्याज पर एक राशि 7 वर्षों में दोगुनी हो जाती है। साधारण ब्याज की समान दर पर यह राशि ______ वर्षों में चार गुना हो जाएगी।

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