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torisob [31]
3 years ago
5

Question Help

Mathematics
1 answer:
lorasvet [3.4K]3 years ago
6 0

Answer:

The speed of the boat is 20 km/hr

Step-by-step explanation:

Let s be the speed of boat in still water

Let d be the distance

Upstream speed = s-4

Jane took 30 min to drive her boat upstream to water-ski at her favorite spot.

So, Distance traveled in upstream =Speed \times time =(s-4) \times \frac{30}{60}

Downstream speed = s+4

So, Distance traveled in downstream = Speed \times time =(s+4) \times \frac{20}{60}

So, (s-4) \times \frac{30}{60}=(s+4) \times \frac{20}{60}

30s-120=20s+80

10s=200

s=20

Hence The speed of the boat is 20 km/hr

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The first quartile can best be described as ______________________.
Zolol [24]

Answer:

A. the median of the lower half of a data set ordered from least to greatest

Step-by-step explanation:

The first quartile can best described as  the median of the lower half of a data set ordered from least to greatest.

Let us explain this with an example, say you're given a set of numbers: {1, 2, 5, 8, 9, 12, 15, 16, 20, 23, 25, 28, 32, 36, 42}. The median for the set is 16, the first quartile is going to be the median of the first half which is 8.

6 0
3 years ago
Drew has more than 4 times as many baseball cards as mark. Katie has fewer than half as many cards as mark. Mark has m baseball
Sphinxa [80]

Answer:

Cards with Mark = 30

Cards with Drew  = 120

Cards with Katie = 12

Step-by-step explanation:

The complete question is

Drew has 4 times as many baseball cards as Mark. Katie has 3 fewer than than half as many cards  as Mark. In all they have 162 baseball cards. How many does each have?

Solution -

Let the number of cards with Mark be "X"

Number of cards with Drew = 4 *X = 4X

Number of Cards with Katies = 0.5 X -3

Sum of all the cards is equal to 162

X+4X + 0.5 X -3 = 162

5.5 X = 165

X = 30

Cards with Mark = 30

Cards with Drew = 4 * 30 = 120

Cards with Katei = 15-3 = 12

5 0
3 years ago
What expression can be used to 80% of 120
12345 [234]

Answer:

59%

Step-by-step explanation:

8 0
3 years ago
Read 2 more answers
The radius of a cylinder is 3 cm and the height is 6 cm.
Ratling [72]

Answer

Step-by-step explanation:

A=2πrh+2πr2=2·π·3·6+2·π·32≈169.646

5 0
3 years ago
Read 2 more answers
Please Help Me! It’s Math! Please!
nadezda [96]

Answer:

D. About 800 years

Step-by-step explanation:

Use the half-life equation:

A = A₀ (½)ⁿ

where A is the final amount,

A₀ is the initial amount,

and n is the number of half-lives.

0.90A₀ = A₀ (½)ⁿ

0.90 = (½)ⁿ

To solve for n, take log of both sides:

log 0.9 = n log 0.5

n = (log 0.9) / (log 0.5)

n = 0.152

It takes 0.152 half-lives.  The half-life of carbon-14 is 5730 years.

0.152 × 5730 years = 871 years

The closest answer is D.

8 0
3 years ago
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