| << Chapter < Page | Chapter >> Page > |
Solve:
 | ||
| Multiply both sides by the LCD, 18. |
 | |
| Simplify. |
 | |
| Distribute. |
 | |
| Solve for . |
 | |
| Check. | ||
 |
||
 |
 |
|
| Simplify. |
 |
|
| Divide. |
 |
To solve applications with proportions, we will follow our usual strategy for solving applications. But when we set up the proportion, we must make sure to have the units correct—the units in the numerators must match and the units in the denominators must match.
When pediatricians prescribe acetaminophen to children, they prescribe 5 milliliters (ml) of acetaminophen for every 25 pounds of the child’s weight. If Zoe weighs 80 pounds, how many milliliters of acetaminophen will her doctor prescribe?
| Identify what we are asked to find, and choose a variable to represent it. | How many ml of acetaminophen will the doctor prescribe? | |
| Let of acetaminophen. | ||
| Write a sentence that gives the information to find it. | If 5 ml is prescribed for every 25 pounds, how much will be prescribed for 80 pounds? | |
| Translate into a proportion–be careful of the units.
|
 | |
| Multiply both sides by the LCD, 400. |
 | |
| Remove common factors on each side. |
 | |
| Simplify, but don't multiply on the left. Notice what the next step will be. |
 | |
| Solve for . |
 | |
| Check. |
 | |
| Is the answer reasonable? | ||
| Yes, since 80 is about 3 times 25, the medicine should be about 3 times 5. So 16 ml makes sense. | ||
 |
||
| Write a complete sentence. | The pediatrician would prescribe 16 ml of acetaminophen to Zoe. |
Pediatricians prescribe 5 milliliters (ml) of acetaminophen for every 25 pounds of a child’s weight. How many milliliters of acetaminophen will the doctor prescribe for Emilia, who weighs 60 pounds?
For every 1 kilogram (kg) of a child’s weight, pediatricians prescribe 15 milligrams (mg) of a fever reducer. If Isabella weighs 12 kg, how many milligrams of the fever reducer will the pediatrician prescribe?
A 16-ounce iced caramel macchiato has 230 calories. How many calories are there in a 24-ounce iced caramel macchiato?
| Identify what we are asked to find, and choose a variable to represent it. | How many calories are in a 24 ounce iced caramel macchiato? | |
| Let in 24 ounces. | ||
| Write a sentence that gives the information to find it. | If there are 230 calories in 16 ounces, then how many calories are in 24 ounces? | |
| Translate into a proportion–be careful of the units.
|
 | |
| Multiply both sides by the LCD, 48. |
 | |
| Remove common factors on each side. |
 | |
| Simplify. |
 | |
| Solve for . |
 | |
 | ||
| Check. | ||
| Is the answer reasonable? | ||
| Yes, 345 calories for 24 ounces is more than 290 calories for 16 ounces, but not too much more. | ||
 |
||
| Write a complete sentence. | There are 345 calories in a 24-ounce iced caramel macchiato. |
At a fast-food restaurant, a 22-ounce chocolate shake has 850 calories. How many calories are in their 12-ounce chocolate shake? Round your answer to nearest whole number.
Yaneli loves Starburst candies, but wants to keep her snacks to 100 calories. If the candies have 160 calories for 8 pieces, how many pieces can she have in her snack?
Josiah went to Mexico for spring break and changed $325 dollars into Mexican pesos. At that time, the exchange rate had $1 US is equal to 12.54 Mexican pesos. How many Mexican pesos did he get for his trip?
| What are you asked to find? | How many Mexican pesos did Josiah get? | |
| Assign a variable. | Let | |
| Write a sentence that gives the information to find it. | If $1 US is equal to 12.54 Mexican pesos, then $325 is how many pesos? | |
| Translate into a proportion–be careful of the units. | ||
 | ||
| Multiply both sides by the LCD, . |
 | |
| Remove common factors on each side. |
 | |
| Simplify. |
 | |
| Check. | ||
| Is the answer reasonable? | ||
| Yes, $100 would be 1,254 pesos. $325 is a little more than 3 times this amount, so our answer of 4075.5 pesos makes sense. | ||
 |
||
| Write a complete sentence. | Josiah got 4075.5 pesos for his spring break trip. |
Notification Switch
Would you like to follow the 'Elementary algebra' conversation and receive update notifications?
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|