In a class of 25 students

1 answer:

4 0

If the mean height of 15 girls is 1.65m, the sum of the girls’ heights is 15×1.65=24.75m.

If the mean height of 10 boys is x metres, the sum of the boys’ heights is 10x m.

The sum of all 25 srudents’ heights is 25×1.682=42.05m.

Therefore, 24.75+10x=42.05, x=(42.05-24.75)/10=1.73m, the mean height of the boys.

You might be interested in

Two integers differ by 12 and the sum of their squares is 74. find the integers.

V125BC [204]

Let x is the smaller integer.
x+12 is the larger integer because two integers differ by 12.
The sum of their square means
x² + (x+12)² = 74
x² + x² + 24x + 144 = 74
2x² + 24x + 70 = 0
2(x² + 12x + 35) = 0
2(x+5)(x+7) = 0
x = -5 or - 7
so we have two answer.
first x = -5 as smaller and 7 as the larger x = -5 + 12 = 7
second x = -7 as smaller and 5 as the larger. x = -7 + 12 = 5

8 0

4 years ago

What is the correct expansion of (x - 2)(x - 5)?

kherson [118]

$▪▪▪▪▪▪▪▪▪▪▪▪▪ {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪$

The equivalent expression is ~

${x}^{2} - 7x + 10$

$\large \boxed{ \mathfrak{Step\:\: By\:\:Step\:\:Explanation}}$

$(x - 2)(x - 5)$

$\small(x \times x) + (x \times - 5) + ( - 2 \times x) + ( - 2 \times - 5)$

${x}^{2} - 5x - 2x + 10$

${x}^{2} - 7x + 10$

$\mathrm{✌TeeNForeveR✌}$

3 0

3 years ago

Read 2 more answers

Journal entries recorded to update general ledger accounts at the end of a fiscal period

serg [7]

Yea so whats the question or is that just a fact<span />

5 0

3 years ago

Read 2 more answers

Genevieve spent $55.20 on gasoline to fill her 15-gallon tank .At another gas station $72.80 on gasoline to fill his 20-gallon t

kifflom [539]

Hi there! I can help you! Okay, so to find the answer for these types of questions, we have to divide the total cost on gas by the number of gallons filled in the tank. With that being said, if you do this correctly, here are your answers.

Genevieve: $3.68
Unnamed Person: $3.64

When you compare the prices, you see that 3.64 < 3.68. With this being the case, the unnamed person spent less per gallon of gas.

7 0

3 years ago

Cost A=0.6489<br><br> take the inverse cosine of both sides

Stolb23 [73]

I am not quite sure what the question asks for,
But this is what i assume it wants:

Cos A= 0.6489
In this given one, we basically find the size of the angle A
we do cosine inverse on both sides to get the size of the angle A
$cos^{-1}$ : It looks like this in the calculator
$cos^{-1}$ × cos A= $cos^{-1}$ (0.6489)
( $cos^{-1}$ and cos cancels out)
A= $cos^{-1}$ (0.6489)
A=49.54°
check:
cos 49.54=0.6489 (its right!)

6 0

3 years ago