Question

A farmer feeds a cow 1,746 milligrams of an antibiotic. Every hour, 27% of the drug breaks down in the cow's body. How much will be left in 8 hours?If necessary, round your answer to the nearest tenth.

Answer 1

Every hour, 27% of the drug breaks down in the cow's body, which means that every hour 73% remains from the previous quantity. To find the a percentage of a given quantity, we multiply this quantity by the percentage value and divide by 100.

To find 73% of a quantity is the same as multiplying by 0.73.

Since every hour 73% remains, every hour this quantity is multiplied by 0.73. Since 8 hours passed, we multiply by 0.73 8 times.

If we do this operation with our initial quantity, we're going to have

`1746*0.73^8=140.807932045\ldots\approx140.8`

There will be 140.8 milligrams of antibiotic.