Answer :
- The cost of the aquarium is $139.
- The cost of 'b' gold barbs at $1.99 each is $1.99b.
- The cost of 'g' guppies at $3.99 each is $3.99g.
- The total cost is the sum of these: $\boxed{139+1.99 b+3.99 g}$
### Explanation
1. Problem Analysis
Lisa purchases an aquarium for $139. She also buys 'b' gold barbs and 'g' guppies. We need to determine the expression that represents the total cost of her purchases.
2. Calculating Cost of Fish
Let's assume the price of each gold barb is $1.99 and the price of each guppy is $3.99. The total cost for the gold barbs would be the number of barbs multiplied by the price per barb, which is $1.99 * b = 1.99b$. Similarly, the total cost for the guppies is the number of guppies multiplied by the price per guppy, which is $3.99 * g = 3.99g$.
3. Finding the Total Cost
To find the total amount Lisa pays, we add the cost of the aquarium to the total cost of the gold barbs and the guppies. This gives us: $139 + 1.99b + 3.99g$.
4. Matching the Expression
Comparing this expression with the given options, we see that the expression $139 + 1.99b + 3.99g$ matches our derived expression. Therefore, this is the correct expression to represent the total amount Lisa pays.
5. Final Answer
The expression that represents the total amount Lisa pays for the aquarium and the fish is $\boxed{139+1.99 b+3.99 g}$.
### Examples
Imagine you're at a carnival. There's an entry fee of $10. Each game costs $2, and each ride costs $3. If you play 'x' games and go on 'y' rides, the total amount you spend can be represented by the expression $10 + 2x + 3y$. This is similar to Lisa's pet store trip, where the aquarium is like the entry fee, and the fish are like the games and rides.
- The cost of 'b' gold barbs at $1.99 each is $1.99b.
- The cost of 'g' guppies at $3.99 each is $3.99g.
- The total cost is the sum of these: $\boxed{139+1.99 b+3.99 g}$
### Explanation
1. Problem Analysis
Lisa purchases an aquarium for $139. She also buys 'b' gold barbs and 'g' guppies. We need to determine the expression that represents the total cost of her purchases.
2. Calculating Cost of Fish
Let's assume the price of each gold barb is $1.99 and the price of each guppy is $3.99. The total cost for the gold barbs would be the number of barbs multiplied by the price per barb, which is $1.99 * b = 1.99b$. Similarly, the total cost for the guppies is the number of guppies multiplied by the price per guppy, which is $3.99 * g = 3.99g$.
3. Finding the Total Cost
To find the total amount Lisa pays, we add the cost of the aquarium to the total cost of the gold barbs and the guppies. This gives us: $139 + 1.99b + 3.99g$.
4. Matching the Expression
Comparing this expression with the given options, we see that the expression $139 + 1.99b + 3.99g$ matches our derived expression. Therefore, this is the correct expression to represent the total amount Lisa pays.
5. Final Answer
The expression that represents the total amount Lisa pays for the aquarium and the fish is $\boxed{139+1.99 b+3.99 g}$.
### Examples
Imagine you're at a carnival. There's an entry fee of $10. Each game costs $2, and each ride costs $3. If you play 'x' games and go on 'y' rides, the total amount you spend can be represented by the expression $10 + 2x + 3y$. This is similar to Lisa's pet store trip, where the aquarium is like the entry fee, and the fish are like the games and rides.
