Question

can you help??? I'd appreciate it if you helped.

Answer 1

What's used?

• Unitary method

Unit means one. Then, what is unitary method? It is finding how much value for one quantity corresponds. We can do this method using a proportion of two quantities.

$\bigstar \sf{value:quantity=unit\;value:unit\;quantity}$

Q. 16

To find:-

• Dollars per cookie

Solution:-

The unit is one cookie.

Let dollars be $x$.

$\bigstar\sf{dollar:cookie=dollar:cookie}$

$\rightarrow 2.08:13=x:1$

Products of extremes and means are equal.

$\rightarrow 13x=2.08$

$\rightarrow x=\dfrac{2.08}{13}$

$\rightarrow x=\dfrac{\cancel{208}^{4}}{\cancel{1300}_{25}}$

$\rightarrow x=0.16$

So, the unit rate is $0.16$ dollars per cookie.

Q. 17

To find:-

• Dollars per yard

Solution:-

The unit is one yard.

Let dollars be $x$.

$\bigstar\sf{dollar:yard=dollar:yard}$

$\rightarrow 9:1\dfrac{2}{3} =x:1$

$\rightarrow 9:\dfrac{5}{3} =x:1$

Products of extremes and means are equal.

$\rightarrow \dfrac{5}{3} x=9$

$\rightarrow x=9\times \dfrac{3}{5}$

$\rightarrow x=\dfrac{27}{5}$

So, the unit rate is $5.4$ dollars per yard.

Q. 18

To find:-

• Dollars per pound

Solution:-

The unit is one pound.

Let dollars be $x$.

$\bigstar\sf{dollar:pound=dollar:pound}$

$\rightarrow 8.58:2=x:1$

Products of extremes and means are equal.

$\rightarrow 2x=8.58$

$\rightarrow x=4.29$

So, the unit rate is $4.29$ dollars per pound.

Q. 19

To find:-

• Miles per hour

Solution:-

The unit is one hour.

Let the miles be $x$.

$\bigstar\sf{miles:hour=miles:hour}$

$\rightarrow \dfrac{2}{3} :\dfrac{1}{4}=x:1$

$\rightarrow \dfrac{1}{4} x=\dfrac{2}{3}$

$\rightarrow x=\dfrac{8}{3}$

So, the unit rate is $\dfrac{8}{3}$ miles per hour.

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