The rule of 70 states that if yt grows at a rate of g percent per year, then the number of years it takes yt to:

с.ifyt grows at a rate of g percent per year, then the number of years it takes yt to double is approximately equal to 70/g

Step-by-step explanation:

The given options

a.ifyt grows at a rate of g percent per year, then the number of years it takes yt to double is approximately equal to g 70

b. if yt grows at a rate of g percent per year, then the number of years it takes yt to double is approximately equal to 70/1

с.i fyt grows at a rate of g percent per year, then the number of years it takes yt to double is approximately equal to 70/g  

d. if yt grows at a rate of g percent per year, then the number of years it takes yt to triple is approximately equal to 70/g  

е.ifyt grows at a rate of g percent per year, then the number of years it takes yt to double is exactly equal to 70/g

The rule of 70 refers to the time period in which the investment you make is doubled. It analyzed that in how many years it took for doubling the amount by considering the specific rate of return  

Now we go through the options and as we can see that the option c meets the requirement as the g represents the growth rate and it fits to the above explanation

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step-by-step explanation:

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starting with:    

5 + x - 12 = 2x - 7   

5 + x - 12 - x = 2x - 7 - x (subtract x from both sides)   

5 - 12 = x - 7 (combine and cancel x's from both sides)   

5 - 12 + 7 = x - 7 + 7 (add 7 to both sides)   

0 = x (add numbers together on both sides)       

so in order for the equation to be true, x must be 0.   

trying x = -0.5   

5 + x - 12 = 2x - 7 (original equation)   

5 + -0.5 - 12 = 2(-0.5) - 7 (plug in value of x)   

5 + -0.5 - 12 = -1 - 7 (did multiplication)   

-7.5 = -8 (did addition on both sides)       

since -7.5 is obviously not equal to -8, the value of -0.5 for x is wrong.   

trying x = 0   

5 + x - 12 = 2x - 7 (original equation)   

5 + 0 - 12 = 2(0) - 7 (plug in value of x)   

5 + 0 - 12 = 0 - 7 (did multiplication)   

-7 = -7 (did addition on both sides)       

since -7 equals -7, that demonstrates that the value of 0 for x is correct.   

trying x = 1   

5 + x - 12 = 2x - 7 (original equation)   

5 + 1 - 12 = 2(1) - 7 (plug in value of x)   

5 + 1 - 12 = 2 - 7 (did multiplication)   

-6 = -5 (did addition on both sides)       

since -6 is obviously not equal to -5, the value of 1 for x is wrong.