문자의 사용과 식의 계산

The width of a rectangle is $2$ meters greater than the length. Let $l$ represent the length of the rectangle. Write an expression for the width of the rectangle.

Adele bought a skirt and a blouse. The skirt cost $\char36 15$ more than the blouse. Let $b$ represent the cost of the blouse. Write an expression for the cost of the skirt.

The number of girls in a second-grade class is $4$ less than the number of boys. Let $b$ represent the number of boys. Write an expression for the number of girls.

Stamps Allie and Loren need to buy stamps. Allie needs four $\char36 0.49$ stamps and nine $\char36 0.02$ stamps. Loren needs eight $\char36 0.49$ stamps and three $\char36 0.02$ stamps.

1. ⓐ How much will Allie’s stamps cost?
2. ⓑ How much will Loren’s stamps cost?
3. ⓒ What is the total cost of the girls’ stamps?
4. ⓓ How many $\char36 0.49$ stamps do the girls need altogether? How much will they cost?
5. ⓔ How many $\char36 0.02$ stamps do the girls need altogether? How much will they cost?

Counting Cash Grant is totaling up the cash from a fundraising dinner. In one envelope, he has twenty-three $\char36 5$ bills, eighteen $\char36 10$ bills, and thirty-four $\char36 20$ bills. In another envelope, he has fourteen $\char36 5$ bills, nine $\char36 10$ bills, and twenty-seven $\char36 20$ bills.

1. ⓐ How much money is in the first envelope?
2. ⓑ How much money is in the second envelope?
3. ⓒ What is the total value of all the cash?
4. ⓓ What is the value of all the $\char36 5$ bills?
5. ⓔ What is the value of all $\char36 10$ bills?
6. ⓕ What is the value of all $\char36 20$ bills?

Buying by the case Joe can buy his favorite ice tea at a convenience store for $\char36 1.99$ per bottle. At the grocery store, he can buy a case of $12$ bottles for $\char36 23.88.$

1. ⓐ Use the distributive property to find the cost of $12$ bottles bought individually at the convenience store. (Hint: notice that $\char36 1.99$ is $\char36 2-\char36 0.01.$)
2. ⓑ Is it a bargain to buy the iced tea at the grocery store by the case?

Multi-pack purchase Adele’s shampoo sells for $\char36 3.97$ per bottle at the drug store. At the warehouse store, the same shampoo is sold as a $\text{3-pack}$ for $\char36 10.49.$

1. ⓐ Show how you can use the distributive property to find the cost of $3$ bottles bought individually at the drug store.
2. ⓑ How much would Adele save by buying the $\text{3-pack}$ at the warehouse store?

Jamal rides his bike at a uniform rate of $12$ miles per hour for $3\frac{1}{2}$ hours. How much distance has he traveled?

Lindsay drove for $5\frac{1}{2}$ hours at $60$ miles per hour. How much distance did she travel?

Trinh walked for $2\frac{1}{3}$ hours at $3$ miles per hour. How far did she walk?

Rey is planning to drive from his house in San Diego to visit his grandmother in Sacramento, a distance of $520$ miles. If he can drive at a steady rate of $65$ miles per hour, how many hours will the trip take?

Lee wants to drive from Phoenix to his brother’s apartment in San Francisco, a distance of $770$ miles. If he drives at a steady rate of $70$ miles per hour, how many hours will the trip take?

Yesenia is $168$ miles from Chicago. If she needs to be in Chicago in $3$ hours, at what rate does she need to drive?

The formula for area of a triangle is $A=\frac{1}{2}bh.$ Solve this formula for $h:$ - ⓐ when $A=90$ and $b=15$

• ⓑ in general

Steve drove for $8\frac{1}{2}$ hours at $72$ miles per hour. How much distance did he travel?

Socorro drove for $4\frac{5}{6}$ hours at $60$ miles per hour. How much distance did she travel?

Yuki walked for $1\frac{3}{4}$ hours at $4$ miles per hour. How far did she walk?

Francie rode her bike for $2\frac{1}{2}$ hours at $12$ miles per hour. How far did she ride?

Connor wants to drive from Tucson to the Grand Canyon, a distance of $338$ miles. If he drives at a steady rate of $52$ miles per hour, how many hours will the trip take?

Megan is taking the bus from New York City to Montreal. The distance is $384$ miles and the bus travels at a steady rate of $64$ miles per hour. How long will the bus ride be?