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3 years ago

How many 9 digit numbers have their first and last digits even?

2 answers:

7 0

There are 900000000 nine-digits numbers and exactly half of them have an even sum of digits (because every number can be paired with another of the opposite parity by changing the last digit).

Katarina [22]3 years ago

6 0

Answer: 200,000,000.

we have 9 spaces we need to fill in

There are 10 total numbers(0–9)

There are 5 even numbers(0,2,4,6,8)

fill from left to right

u cannot start with 0 so pick another number 2,4,6,8 any of those

4*10^7*5= 20*10^7 = 2*10^8

200,000,000.

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One boat travelling 15 mph goes 47 miles downstream in the same amount of time that another boat going 20 mph goes 40 miles upst

vazorg [7]

Answer:

3.9 mi/h

Step-by-step explanation:

We assume that the given speeds are the speeds of the boats relative to the water. If c is the speed of the current, we have ...

time = distance/speed

47/(15 +c) = 40/(20 -c)

47(20 -c) = 40(15 +c) . . . . . . multiply by (20-c)(15+c)

940 -600 = 40c +47c . . . . . add 47c-600

340 = 87c . . . . . . . . . . . . . . . simplify; next divide by 87

c = 340/87 ≈ 3.9080 . . . . mi/h

The speed of the current is about 3.9 mi/h.

6 0

4 years ago

Which inverse operations could you use to solve the equation m5−8=−6? Select all that apply.

Norma-Jean [14]

Answer:

Correct option: C

Step-by-step explanation:

To solve the equation m*5 - 8 = -6, we can use the following steps:

step1: sum 8 in both sides, to make m*5 be the only term in the left side.

m*5 = 2

step2: divide both sides by 5, then we will have 'm' isolated in the left side.

m = 2/5

So the operations we could use is: add 8 to each side and then divide each side by 5.

Correct option: C

8 0

3 years ago

A baseball player hits a ball at an angle of 52 degree and at a height of 4.8 ft. If the ball's initial velocity after being hit

sergeinik [125]

I think the answer is c.7.43

8 0

3 years ago

"The voice of the sea is seductive; never ceasing, whispering, clearing, murmuring, inviting the soul to wander for a spell in t

klio [65]

For me, the significance of this quote is to emphasize the feeling of peace and comfort we get that is brought about by the sea. It uses figure of speech, particularly, personification. By doing so, it creates a connection from the reader to what the speaker wants to deliver.

8 0

4 years ago

Find the surface area of a

Softa [21]

Answer:

About 706.5 square inches.

Step-by-step explanation:

Surface area of a sphere is: $SA=4\pi r^2$