Question

plz solve this on explanatory manner....

Answer 1

$( \frac{1}{2} + \frac{1}{3} + \frac{1}{4} ) \times \frac{3}{4}$
Solving bracket will give answer of 1.08.
Multiplying by 0.75
$( \frac{3}{4} )$
Will give answer of 0.81

Answer 2

there is your answer..
(​2​​1​​+​3​​1​​+​4​​1​​)×​4​​3​​ 
Solving bracket will give answer of 1.08 or 13/12.
Multiplying by 0.75  or 3/4
13/12 multipled 3/4 
we get answer 0.8125 or 13/16