All categories

3 years ago

Amir can run 15 kilometers in one hour. How many kilometers can Amir run per minute?

Mathematics

1 answer:

inysia [295]3 years ago

5 0

Amir can run 0.25 kilometers per minute.

You might be interested in

Jess is 12 years less than half as old as Mac. The sum of their age is 87. How old is each person?

laila [671]

Answer:

The age of each person is:

Jess is 21 years old.
Mac is 66 years old.

Step-by-step explanation:

To solve this problem you must make two equations. First, we name Jess and Mac as variables:

j = Jess age.

m = Mac age.

Now we make the equations, the first equation has the information "Jess is 12 years less than half as old as Mac":

1. $j=(\frac{m}{2})-12$

The second equation has the information "The sum of their age is 87":

2. $j+m=87$

Now, we replace the first equation in the second one:

$(\frac{m}{2}-12) +m=87$

And we operate:

$\frac{m-24}{2} +m=87$
$\frac{m-24+2m}{2}=87$
$\frac{3m-24}{2}=87$

We clear the variable m:

$3m-24=87*2$
$3m=174+24$
$m=\frac{198}{2}$
$m=66$

How we know Mac's age is 66 years old, we can identify Jess' age with the second equation:

$j+m=87$

We replace the value of m:

$j+66=87$

And clear the variable j:

$j=87-66$
$j=21$

In the end, Jess's age is 21 years old.

4 0

3 years ago

Hi, I need help with how it work out the angles on this please

kap26 [50]

All the angles in any triangle add up to make 180°.

4 0

3 years ago

56 is 75% of what number? Show your work.

zhannawk [14.2K]

75% × x = 56 or, 75/100 × x = 56
Multiplying both sides by 100 and dividing both sides by 75,
we have x = 56 × 75/100
x = 74.667

3 0

2 years ago

Chad drove 168 miles in 3 hours How many miles per hour did Chad drive?

Masja [62]

He drove 56 miles because if you divide 168 and 3 it equals 56.

4 0

2 years ago

Two chemicals A and B are combined to form a chemical C. The rate, or velocity, of the reaction is proportional to the product o

Keith_Richards [23]

Answer:

32.1 g

Step-by-step explanation:

In each 3 grams of C, there are 2 grams of A and 1 gram of B. So, for some amount C, the amount remaining of A is 40 -(2C/3), and the amount remaining of B is (50 -C/3). Since the reaction rate is proportional to the product of these amounts, we have ...

C' = k(40 -2C/3)(50 -C/3) = (2k/9)(60 -C)(150 -C) . . . for some constant k

This is separable differential equation with a solution of the form ...

ln((150 -C)/(60 -C)) = at + b

We know that C(0) = 0, so b=ln(150/60) = ln(2.5). And we know that C(10) = 20, so ln(130/40) = 10a +ln(2.5) ⇒ a = ln(1.3)/10

Then our equation for C is ...

ln((150 -C)/(60 -C)) = t·ln(1.3)/10 +ln(2.5)

For t=20, this is ...

ln((150 -C)/(60 -C)) = 2ln(1.3) +ln(2.5) = ln(2.5·1.3²) = ln(4.225)

Taking antilogs, we have ...

(150 -C)/(60 -C) = 4.225

1 +90/(60 -C) = 4.225

C = 60 -90/3.225 ≈ 32.093 . . . . . grams of product in 20 minutes

In 20 minutes, about 32.1 grams of C are formed.

7 0

2 years ago