How do you solve this ?

irinina [24]

Answer:

The are 8 dimes and 12 nickels

Step-by-step explanation:

1.We set n+d=20 because 20 is the total number of dimes and nickels in the jar.We have $0.05 n because for ever nickel,we earn $0.05.Adding this to the value of dimes,represented similarly by $0.1,then we set this to the amount of money we have in total,which is $1.40.

2.Subtract d from both sides of the first equation to get it by itself.Substitute-d for n in the second equation.The divide both sides by 0.5 to obtain the answer.

3.Substitute 8 in for d to obtain the value or n.

6 0

3 years ago

7x + y^2; if x = -4 and y = 5

const2013 [10]

Answer:

-3

Step-by-step explanation:

7x + y^2

subsitute

= 7x=7x-4= -28

=y^2=5^2= 25

-28 + 25= -3

8 0

3 years ago

HALLP QUICKKKK

Rina8888 [55]

To solve this we are going to use the formula for speed: $S= \frac{d}{t}$
where
$S$ is the speed
$d$ is the distance
$t$ is the time

Let $S_{l}$ be the speed of the boat in the lake, $S_{a}$ the speed of the boat in the river, $t_{l}$ the time of the boat in the lake, and $t_{a}$ the time of the boat in the river.

We know for our problem that the current of the river is 2 km/hour, so the speed of the boat in the river will be the speed of the boat in the lake minus 2km/hour:
 $S_{a}=S_{l}-2$
We also know that in the lake the boat sailed for 1 hour longer than it sailed in the river, so:
 $t_{l}=t_{a}+1$

Now, we can set up our equations.
Speed of the boat traveling in the river:
 $S_{a}= \frac{6}{t_{a} }$
But we know that $S_{a}=S_{l}-2$ , so:
$S_{l}-2= \frac{6}{t_{a} }$ equation (1)

Speed of the boat traveling in the lake:
$S_{l}= \frac{15}{t_{l} }$
But we know that $t_{l}=t_{a}+1$ , so:
$S_{l}= \frac{15}{t_{a}+1}$ equation (2)

Solving for $t_{a}$ in equation (1):
$S_{l}-2= \frac{6}{t_{a} }$
$t_{a}= \frac{6}{S_{l}-2}$ equation (3)

Solving for $t_{a}$ in equation (2):
$S_{l}= \frac{15}{t_{a}+1}$
$t_{a}+1= \frac{15}{S_{l}}$
$t_{a}=\frac{15}{S_{l}}-1$
$t_{a}= \frac{15-S_{l}}{S_{l}}$ equation (4)

Replacing equation (4) in equation (3):
$t_{a}= \frac{6}{S_{l}-2}$
$\frac{15-S_{l}}{S_{l}}=\frac{6}{S_{l}-2}$

Solving for $S_{l}$ :
$\frac{15-S_{l}}{S_{l}}=\frac{6}{S_{l}-2}$
$(15-S_{l})(S_{l}-2)=6S_{l}$
$15S_{l}-30-S_{l}^2+2S_{l}=6S_{l}$
$S_{l}^2-11S_{l}+30=0$
$(S_{l}-6)(S_{l}-5)=0$
$S_{l}=6$ or $S_{l}=5$

We can conclude that the speed of the boat traveling in the lake was either 6 km/hour or 5 km/hour.

3 0

3 years ago

Rewrite the expression using GCF and distributive property. 64x-24

Ede4ka [16]

The greatest common factor between 64 and 24 is 8

Let's divide both terms in the expression by 8 and leave the expression in parenthesis...

Like this!

64x -24

$\frac{64x}{8} - \frac{24}{8}$