If 2 sodas and 4 hamburgers are $12.00 and 4 sodas and 2 hamburgers are $9.00 how much is a single hamburger?
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2s + 4h = 12, (1) 4s + 2h = 9. (2) Multiply (1) by 2. You will get 4s + 8h = 24, (1') 4s + 2h = 9. (2') Distract (2') from (1'). You will get 8h - 2h = 24 - 9, or 6h = 15 ---> h =  =  = 2.5. Thus one hamburger price is $2.50. Then from (1) s =  = 1. Answer. One hamburger price is $2.50 and 1 soda costs $1.00.
There is even more elegant way to solve the problem.
Simply add all hamburgers and all sodas. 6 hamburgers and 6 sodas. $12 + $9 = $21.
Hence, 1 hamburger + 1 soda =  = $3.50.
Having this, everybody can solve to the end in this way, actually, without equations and using the mental math only.
Question: A man measures the angle of elevation to the top of a mountain to be 12 degrees. He drives 7 miles closer and finds the angle of elevation to be 37 degrees. How high is the mountain?
Answer:
x+(x+7)
Step-by-step explanation:
sum=add all together
One less limb than yesterday! so let’s assume like a regular human the mutant has 4 limbs. he grows another 5 and now he’s got 9 limbs. he loses 12 so 9-12 equals -3, plus 2 is -1.
Answer:
-3/4
Step-by-step explanation:
the rate of change is the slope of the line
7-3/0-(-4) = -3/4
Answer:
son = 10 , father = 40
Step-by-step explanation:
Let Five years ago the age of son be x years and age of father be 7x years
Present age of son =x+5
Present age of father =7x+5
5 years later their age will (x+10) and (7x+10)
∴7x+10=3(x+10)
7x−3x=20
4x=20
x=5
So, the present age of son=x+5=5+5=10years
and the present age of father=7x+5=35+5=40years
hope it helps you
