Final answer:
To calculate the amount of vitamin in the drink that has 140% of the RDA, multiply 1.40 by the RDA of 20 mg to get 28 mg.
Step-by-step explanation:
If a drink has 140% of the recommended daily allowance (RDA) for a certain vitamin and the RDA for the vitamin is 20 mg, then the amount of the vitamin in the drink can be found by calculating 140% of 20 mg.
To find 140% of a number, you convert the percentage to a decimal (140% = 1.40) and multiply that by the number. So, you would calculate 1.40 × 20 mg:
1.40 × 20 mg = 28 mg.
Therefore, the drink contains 28 milligrams of the vitamin, which is 140% of the RDA.