Let's assume the original balance of the account is x.
The balance after earning interest is 7/6 of the original balance, so it is 7/6 * x = (7/6)x.
Since the balance after earning interest is 420, (7/6)x = 420.
To find the interest, we need to subtract the original balance from the balance after earning interest: (7/6)x - x = 420 - x.
Combining like terms, we have (7/6 - 1)x = 420 - x.
Simplifying further, we get (1/6)x = 420 - x.
Moving terms around, 420 - x = (1/6)x.
Adding x to both sides, we have 420 = (7/6)x.
Dividing both sides by (7/6), we get x = 360.
The interest earned is the difference between the balance after earning interest and the original balance: (7/6)x - x = 420 - 360 = 60.
Therefore, it earned 60 in interest.
after earning interest, the balance of an account is 420. the balance is 7/6 of the original balance. how much interest did it earn.
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