1-20-1-30-1-42-1-56-1-72-1-90-1-110-1-132 is equal to-

The correct option is D 1/6 Given exp.. #160; =1/4×5+1/5×6+1/6×7+1/7×8+1/8×9 #160;+1/9×0+1/10×11+1/11×12 = ( 1/4 1/5 )+ ( 1/5 1/6 )+ ( 1/6 1/ ...

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Byju's Answer

Standard VIII

Mathematics

Commutative Property of Rational Numbers

1/20+1/30+1/4...

Question

$\frac{1}{20} + \frac{1}{30} + \frac{1}{42} + \frac{1}{56} + \frac{1}{72} + \frac{1}{90} + \frac{1}{110} + \frac{1}{132}$ is equal to:

\frac{1}{8}

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\frac{1}{7}

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\frac{1}{6}

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\frac{1}{10}

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Solution

The correct option is D $\frac{1}{6}$
Given exp.. $= \frac{1}{4 \times 5} + \frac{1}{5 \times 6} + \frac{1}{6 \times 7} + \frac{1}{7 \times 8} + \frac{1}{8 \times 9} + \frac{1}{9 \times 0} + \frac{1}{10 \times 11} + \frac{1}{11 \times 12}$
$= (\frac{1}{4} - \frac{1}{5}) + (\frac{1}{5} - \frac{1}{6}) + (\frac{1}{6} - \frac{1}{7}) + (\frac{1}{7} - \frac{1}{8}) + (\frac{1}{4} - \frac{1}{9}) + (\frac{1}{9} - \frac{1}{10}) + (\frac{1}{10} - \frac{1}{11}) + (\frac{1}{11} - \frac{1}{12})$

$= \frac{1}{4} - \frac{1}{12} = \frac{3 - 1}{12} = \frac{2}{12} = \frac{1}{6}$

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Similar questions

Q. Find the sum of

\frac{1}{6} + \frac{1}{6} + \frac{1}{12} + \frac{1}{20} + \frac{1}{30} + \frac{1}{42} + \frac{1}{56} + \frac{1}{72} + \frac{1}{90} + \frac{1}{110} + \frac{1}{132}

Q. The sum of the fractions

\frac{1}{2} + \frac{1}{6} + \frac{1}{12} + \frac{1}{20} + \frac{1}{30} + \frac{1}{42} + \frac{1}{56} + \frac{1}{72} + \frac{1}{90} + \frac{1}{110} + \frac{1}{132}

\frac{1}{30} + \frac{1}{42} + \frac{1}{56} + \frac{1}{72} + \frac{1}{90} + \frac{1}{110}

is equal to : __.

$\frac{1}{(\sqrt{9} - \sqrt{8})} - \frac{1}{(\sqrt{8} - \sqrt{7})} + \frac{1}{(\sqrt{7} - \sqrt{6})} - \frac{1}{(\sqrt{6} - \sqrt{5})} + \frac{1}{(\sqrt{5} - \sqrt{4})}$ is equal to:

Q. The value of

\frac{1}{\sqrt{9} - \sqrt{8}} - \frac{1}{\sqrt{8} - \sqrt{7}} + \frac{1}{\sqrt{7} - \sqrt{6}} - \frac{1}{\sqrt{6} - \sqrt{5}} + \frac{1}{\sqrt{5} - \sqrt{4}}

is equal to

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120+130+142+156+172+190+1110+1132 is equal to:

The correct option is D 16Given exp.. =14×5+15×6+16×7+17×8+18×9+19×0+110×11+111×12=(14−15)+(15−16)+(16−17)+(17−18)+(14−19)+(19−110)+(110−111)+(111−112)=14−112=3−112=212=16

$\frac{1}{20} + \frac{1}{30} + \frac{1}{42} + \frac{1}{56} + \frac{1}{72} + \frac{1}{90} + \frac{1}{110} + \frac{1}{132}$ is equal to: