Can someone please help me with this question, I'm stuck !

Two customers went to a post office to buy postcards and large envelopes. Each postcard

astraxan [27]

The right answer is Option A.

Step-by-step explanation:

Let,

x be the postcards

y be the large envelops

According to given statement;

14x+5y=12 Eqn 1

10x+15y=24.80 Eqn 2

Multiplying Eqn 1 by 3;

$3(14x+5y=12)\\42x+15y=36\ \ \ Eqn \ 3$

Subtracting Eqn 2 from Eqn 3;

$(42x+15y)-(10x+15y)=36-24.80\\42x+15y-10x-15y=11.20\\32x=11.20\\$

Dividing both sides by 32

$\frac{32x}{32}=\frac{11.20}{32}\\x=0.35$

Putting x=0.35 in Eqn 1;

$14(0.35)+5y=12\\4.90+5y=12\\5y=12-4.90\\5y=7.10$

Dividing both sides by 5

$\frac{5y}{5}=\frac{7.10}{5}\\y=1.42$

Therefore, one large envelope costs $1.42

The right answer is Option A.

Keywords: linear equations, subtraction

Learn more about linear equations at:

#LearnwithBrainly

4 0

3 years ago

Which number produces a rational number when multiplied by 0.5?

xxMikexx [17]

If the number begins by being rational, multiplying by 0.5 will not change whether or not it is rational. It will remain rational.

That would include any even number 12 * 0.5 = 6

12 started out as rational, so the answer is rational (6)

Any odd number is also rational

23 * 0.5 = 11.5

23 and 11.5 are both rational.

3.636363636 ... is rational so when multiplied by 0.5 the result will be rational.

1.818181818....

So if we start with something irrational like pi

then pi * 0.5 is not rational.

If you have choices, please list them.

4 0

3 years ago

Leila, Charlie, and Joe have a total of $144 in their wallets. Joe has 4 times what Leila has. Charlie has $6 more than Leila. H

ollegr [7]

Answer:

The amounts of money each has are:

Joe = $92

Charlie = $29

Leila = $23

Step-by-step explanation:

To solve this, we will convert the statements into an equation, and use that to solve for the unknowns, as follows:

total amount = $144

Let Leila's share be S

Joe's share = 4 times Leila's = 4S

Charlie's share = $6 + Leila's share = 6 + S

Joe's share + Charlie's Share + Leila's Share = $144

4S + (6 + S) + S = 144

4S + 6 + S + S = 144

4S + 2S + 6 = 144

6S + 6 = 144

6S = 144 - 6 = 138

S = 138 ÷ 6 = $23

Therefore Leila's share 'S' = $23

Joe share= 4S = 4 × 23 = $92

Charlie's share = 6 + 23 = $29

8 0

3 years ago

Ann is adding water to a swimming pool at a constant rate. The table below shows the amount of water in the pool after different

N76 [4]

Answer:

(a) As time increases, the amount of water in the pool increases.

11 gallons per minute

(b) 65 gallons

Step-by-step explanation:

From inspection of the table, we can see that as time increases, the amount of water in the pool increases.

We are told that Ann adds water at a constant rate. Therefore, this can be modeled as a linear function.

The rate at which the water is increasing is the rate of change (which is also the slope of a linear function).

Choose 2 ordered pairs from the table:

$\textsf{let}\:(x_1,y_1)=(8, 153)$

$\textsf{let}\:(x_2,y_2)=(12,197)$

Input these into the slope formula:

$\textsf{slope}\:(m)=\dfrac{y_2-y_1}{x_2-x_1}=\dfrac{197-153}{12-8}=\dfrac{44}{4}=11$

Therefore, the rate at which the water in the pool is increasing is:

11 gallons per minute

To find the amount of water that was already in the pool when Ann started adding water, we need to create a linear equation using the found slope and one of the ordered pairs with the point-slope formula:

$y-y_1=m(x-x_1)$

$\implies y-153=11(x-8)$

$\implies y-153=11x-88$

$\implies y=11x-88+153$

$\implies y=11x+65$

When Ann had added no water, x = 0. Therefore,

$y=11(0)+65$

$y=65$

So there was 65 gallons of water in the pool before Ann starting adding water.

3 0

2 years ago

Read 2 more answers

On Thursday the basketball coach ordered 12 pizzas for 36 players who came in for practice. How many pizzas does the coach need

Paraphin [41]

Answer:16

Step-by-step explanation:Next day there will be (36+12) or 48 players.

For 36 players 12 pizzas are needed

For 1 player 12/36 pizzas are needed

For 48 players 12/36*48 or 16 pizzas are needed

3 0

2 years ago