Answer:
Step-by-step explanation
- Let x be the number of adults and y the number of kids
We can then write this two equations :
x+y= 33
15x+7y= 311
- let's solve the two eaquations
to do that we should combine them both in a way that help us get rid of one of the variables.
Let's multiply the first equation by -7 to get rid of y by adding it to thr second equation
-7x-7y= -231
now add both equations .
15x+7y-7x-7y=311-231
we get : 8x = 80
as you notice y is gone and we get a classic easy equation to solve
x= 80/8
= 10
so the number of adults is 10
let's go back to the first equation ( x+y= 33) and replace x with 10
10+y= 33
y= 33-10
=23
let's check using the second equation :
(10*15)+(23*7) = 311
that is true
so :
- the number of adults is 10
- the number of kids is 23
8 times 18 is 144. then take that and divide it by 60 seconds which equals a minute. your answer is 2 minutes and 40 seconds
Answer:
x ≈ 83.533
y = 9105.13
Step-by-step explanation:
Step 1: Substitution
109x = 79x + 2506
30x = 2506
x = 83.533
Step 2: Plug <em>x</em> in
y = 109(83.533)
y = 9105.13
Graphically:
Answer:
17.8 cm
Step-by-step explanation:
In the 17 hours between heights of 18.6 cm and 15.2 cm, the candle lost 3.4 cm in height. That is, the height decreased at the rate of ...
(-3.4 cm)/(17 h) = -0.2 cm/h
In the 4 hours between 12 hours and 16 hours of burning time, the candle will have changed its height by (4 h)(-0.2 cm/h) = -0.8 cm.
The height at 16 hours of burning is then 18.6 cm -0.8 cm = 17.8 cm.
