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3 years ago

) A bus travels 400 km in 4.5 hours. (5 total)

Mathematics

1 answer:

Harrizon [31]3 years ago

4 0

V = 400/4.5 (km/hr)
v = 88.89 km/hr

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Sam is buying a pair of water skis that are on sale for 2/3 of the original price. After he uses a $25 gift certificate the tota

Alexus [3.1K]

Answer:

$210

Step-by-step explanation:

The first thing we can do is to add the $25 back on to the total cost.

25 + 115 = 140.

We do this because he Sam used a gift certificate on the ski's that are already 2/3 of the original price.

Now, to find the original price we can use this equation:

$\frac{2}{3} x = 140$

X represents the original price.

To solve this equation you would flip 2/3 to 3/2 and multiply that by 140, as seen below:

$(\frac{3}{2}) \frac{2}{3}x = 140 (\frac{3}{2})$

Now you can solve:

$x = \frac{420}{2} \\x = 210$

We can check this answer by multiplying 210 by 2/3

(210)(2/3) = 140

Remember, Sam used a gift certificate for $25

140 - 25 = $115

Therefore, the original price of the skis is $210.

<em>I hope this helps!!</em>

6 0

3 years ago

Evaluate S5 for 300 + 150 + 75 + … and select the correct answer below. 18.75 93.75 581.25 145.3125

Savatey [412]

we have that

$300 + 150 + 75 +...$

Let

$a1=300\\ a2=150\\ a3=75$

we know that

$\frac{a2}{a1} =\frac{150}{300} \\\\ \frac{a2}{a1}=0.5 \\ \\ a2=a1*0.50$

$\frac{a3}{a2} =\frac{75}{150} \\\\ \frac{a3}{a2}=0.5 \\ \\ a3=a2*0.50$

$a(n+1)=an*0.50$

Is a geometric sequence

Find the value of $a4$

$a(4)=a3*0.50$

$a(4)=75*0.50$

$a(4)=37.5$

Find the value of $a5$

$a(5)=a4*0.50$

$a(5)=37.5*0.50$

$a(5)=18.75$

Find $S5$

$S5=a1+a2+a3+a4+a5\\ S5=300+150+75+37.5+18.75\\ S5=581.25$

therefore

the answer is

$581.25$

Alternative Method

Applying the formula

$S_n=\frac{a_1 (1-r^n)}{1-r} \\\\a_1=300 \\ r=\frac{1}{2}\\\\ S_5=\frac{300(1-(\frac{1}{2})^5)}{1-\frac{1}{2}}\\\\=\frac{300(1-\frac{1}{32})}{\frac{1}{2}}\\\\=\frac{300 \times \frac{31}{32}}{\frac{1}{2}}\\\\=\frac{75 \times \frac{31}{8}}{\frac{1}{2}}\\\\=\frac{\frac{2325}{8}}{\frac{1}{2}}\\\\=\frac{2325}{8} \times 2\\\\=\frac{2325}{4}\\\\=581 \frac{1}{4}\\\\=581.25$