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Helga [31]
3 years ago
10

when oxygen reacts with hydrogen it has the capacity to release 29 kilojoules of energy. Inside a fuel cell, oxygen reacts with

hydrogen to produce 23 kilojoules of useful energy. The rest of the energy is lost as heat. Whats the efficiency percent of the fuel cell?
Mathematics
1 answer:
Pepsi [2]3 years ago
4 0

Answer:

79

Step-by-step explanation:

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Which of the following inequalities are true?
yarga [219]

Answer:

i think its B or D sorry if I'm wrong

3 0
2 years ago
Solve this system of linear equations. separate the x- and y- values with a coma. -12x=-75-11y
ycow [4]
Solve the following system:
{-12 x = -11 y - 75 | (equation 1)
{-5 x = -11 y - 89 | (equation 2)
Express the system in standard form:
{-(12 x) + 11 y = -75 | (equation 1)
{-(5 x) + 11 y = -89 | (equation 2)
Subtract 5/12 × (equation 1) from equation 2:
{-(12 x) + 11 y = -75 | (equation 1)
{0 x+(77 y)/12 = (-231)/4 | (equation 2)
Multiply equation 2 by 12/77:
{-(12 x) + 11 y = -75 | (equation 1)
{0 x+y = -9 | (equation 2)
Subtract 11 × (equation 2) from equation 1:
{-(12 x)+0 y = 24 | (equation 1)
{0 x+y = -9 | (equation 2)

Divide equation 1 by -12:
{x+0 y = -2 | (equation 1)
{0 x+y = -9 | (equation 2)
Collect results:
Answer:  {x = -2                {y = -9

please note that the parentheses "{" should span over both equations but the editor doesn't allow that so I should it on both line, See attached example.










4 0
3 years ago
75 girls at a summer camp were asked to complete a survey about their favorite outdoor activity. 27 girls chose swimming and 32
Oduvanchick [21]

ANSWER

Find out the expression gives the percent of survey participants who chose swimming.

To proof

As given

75 girls at a summer camp were asked to complete a survey about their favorite outdoor activity.

27 girls chose swimming

32 girls chose hiking.

FORMULA

Percentage = \frac{Part\times100}{whole}

total girls  = 75

girls chose swimming = 27

put in the formula

= \frac{27\times100}{75}

= 36%

36% of survey participants who chose swimming

Hence proved

3 0
3 years ago
Read 2 more answers
21 divided by 15.015 step my step diving decimals
ser-zykov [4K]

Answer:

0.715

Step-by-step explanation:

4 0
3 years ago
Gabby received change worth $2.10. She received 3 more dimes than nickels and 4 less quarters than nickels. How many of each kin
xz_007 [3.2K]

Answer:

Gabby received

7 nickels

10 dimes

3 quarters

Step-by-step explanation:

Let

x----> the number of dimes

y----> the number of nickels

z---> the number of quarters

Remember that

1 dime=$0.10

1 nickel=$0.05

1 quarter=$0.25

we know that

0.10x+0.05y+0.25z=2.10 ------> equation A

x=y+3-----> equation B

z=y-4 -----> equation C

substitute equation B and equation C in equation A and solve for y

0.10(y+3)+0.05y+0.25(y-4)=2.10

0.10y+0.30+0.05y+0.25y-1=2.10

0.40y=2.10-0.30+1

0.40y=2.80

y=7 nickels

<em>Find the value of x</em>

x=y+3 -----> x=7+3=10 dimes

<em>Find the value of z</em>

z=y-4 -----> z=7-4=3 quarters

therefore

Gabby received

7 nickels

10 dimes

3 quarters

6 0
3 years ago
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