Question

Please tell fast
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Answer 1

Answer:

Answer is -1.66666666667

Step-by-step explanation:

First we have to add 1/2 20 times = 1/2 x 20 = 10/2

Then we have to add 1/3 30 times = 1/3 x 30 = 10/3

Now we have subtract 10/2 and 10/3 = 10/3 - 10/2

                                                             =  -1.66666666667

Answer 2

Answer:

The value of  $\left\{\dfrac{1}{2} +\dfrac{1}{2} +\dfrac{1}{2} +\cdots 20 \ times \right\}-\left\{\dfrac{1}{3} +\dfrac{1}{3} +\dfrac{1}{3} +\cdots 30 \ times \right\}$ is $0$.

Step-by-step explanation:

We need to calculate the value of,

$\left\{\dfrac{1}{2} +\dfrac{1}{2} +\dfrac{1}{2} +\cdots 20 \ times \right\}-\left\{\dfrac{1}{3} +\dfrac{1}{3} +\dfrac{1}{3} +\cdots 30 \ times \right\}$

We can calculate the sum in each bracket separately.

In the first bracket, we need to add $\frac{1}{2}$ , 20 times. This is the same as multiplying the number by 20. So we have

$\left\{\dfrac{1}{2} +\dfrac{1}{2} +\dfrac{1}{2} +\cdots 20 \ times \right\} =\dfrac{1}{2}\times 20 =10$

Similarly,

$\left\{\dfrac{1}{3} +\dfrac{1}{3} +\dfrac{1}{3} +\cdots 30 \ times \right\}=\dfrac{1}{3}\times 30=10$

Hence it follows that,

$\left\{\dfrac{1}{2} +\dfrac{1}{2} +\dfrac{1}{2} +\cdots 20 \ times \right\}-\left\{\dfrac{1}{3} +\dfrac{1}{3} +\dfrac{1}{3} +\cdots 30 \ times \right\} = 10-10=0$