Given : Anne buys 600 packets of mints.
Given : Of these 600 packets of mints, 34% are small packets and 40% are large packets.
Total % of small and large packets is (34 + 40) = 74%
It means : The remaining percentage is of the medium packets of mints which were brought by Anne.
% of medium packets brought by Anne : (100 - 74) = 26%
![:\implies \textsf{Number of medium packets brought by Anne : $\left(\dfrac{26}{100} \times 600\right)$}](https://tex.z-dn.net/?f=%3A%5Cimplies%20%5Ctextsf%7BNumber%20of%20medium%20packets%20brought%20by%20Anne%20%3A%20%24%5Cleft%28%5Cdfrac%7B26%7D%7B100%7D%20%5Ctimes%20600%5Cright%29%24%7D)
![:\implies \textsf{Number of medium packets brought by Anne : $\left(26 \times 6\right)$ = 156}](https://tex.z-dn.net/?f=%3A%5Cimplies%20%5Ctextsf%7BNumber%20of%20medium%20packets%20brought%20by%20Anne%20%3A%20%24%5Cleft%2826%20%5Ctimes%206%5Cright%29%24%20%3D%20156%7D)
Given : Ben buys 400 packets of mints.
![\textsf{Given : Of these 400 packets of mints, $\dfrac{3}{10}$ are small and $\dfrac{1}{10}$ are large}](https://tex.z-dn.net/?f=%5Ctextsf%7BGiven%20%3A%20Of%20these%20400%20packets%20of%20mints%2C%20%24%5Cdfrac%7B3%7D%7B10%7D%24%20are%20small%20and%20%24%5Cdfrac%7B1%7D%7B10%7D%24%20are%20large%7D)
![\implies \textsf{Total fraction of small and large packets brought by Ben :$\left(\dfrac{3}{10} + \dfrac{1}{10}\right)$}](https://tex.z-dn.net/?f=%5Cimplies%20%5Ctextsf%7BTotal%20fraction%20of%20small%20and%20large%20packets%20brought%20by%20Ben%20%3A%24%5Cleft%28%5Cdfrac%7B3%7D%7B10%7D%20%2B%20%5Cdfrac%7B1%7D%7B10%7D%5Cright%29%24%7D)
It means : The remaining fraction is of the medium packets of mints which were brought by Ben.
![\implies \textsf{Fraction of medium packets brought by Ben : $\left(1 - \dfrac{3}{10} - \dfrac{1}{10}\right)$}](https://tex.z-dn.net/?f=%5Cimplies%20%5Ctextsf%7BFraction%20of%20medium%20packets%20brought%20by%20Ben%20%3A%20%24%5Cleft%281%20-%20%5Cdfrac%7B3%7D%7B10%7D%20-%20%5Cdfrac%7B1%7D%7B10%7D%5Cright%29%24%7D)
![\implies \textsf{Fraction of medium packets brought by Ben : $\left(1 - \dfrac{4}{10}\right)$ = $\dfrac{6}{10}$}](https://tex.z-dn.net/?f=%5Cimplies%20%5Ctextsf%7BFraction%20of%20medium%20packets%20brought%20by%20Ben%20%3A%20%24%5Cleft%281%20-%20%5Cdfrac%7B4%7D%7B10%7D%5Cright%29%24%20%3D%20%24%5Cdfrac%7B6%7D%7B10%7D%24%7D)
![:\implies \textsf{Number of medium packets brought by Ben : $\left(\dfrac{6}{10} \times 400\right)$}](https://tex.z-dn.net/?f=%3A%5Cimplies%20%5Ctextsf%7BNumber%20of%20medium%20packets%20brought%20by%20Ben%20%3A%20%24%5Cleft%28%5Cdfrac%7B6%7D%7B10%7D%20%5Ctimes%20400%5Cright%29%24%7D)
![:\implies \textsf{Number of medium packets brought by Anne : $\left(6 \times 40\right)$ = 240}](https://tex.z-dn.net/?f=%3A%5Cimplies%20%5Ctextsf%7BNumber%20of%20medium%20packets%20brought%20by%20Anne%20%3A%20%24%5Cleft%286%20%5Ctimes%2040%5Cright%29%24%20%3D%20240%7D)
Given : Chas buys 210 small packets of mints.
Given : Number of small packets : number of medium packets = 3 : 4
![\implies \mathsf{\dfrac{210}{number \ of \ medium \ packets} = \dfrac{3}{4}}](https://tex.z-dn.net/?f=%5Cimplies%20%5Cmathsf%7B%5Cdfrac%7B210%7D%7Bnumber%20%5C%20of%20%5C%20medium%20%5C%20packets%7D%20%3D%20%5Cdfrac%7B3%7D%7B4%7D%7D)
![\implies \mathsf{Number \ of \ medium \ packets = \left(210 \times \dfrac{4}{3}\right)}](https://tex.z-dn.net/?f=%5Cimplies%20%5Cmathsf%7BNumber%20%5C%20of%20%5C%20medium%20%5C%20packets%20%3D%20%5Cleft%28210%20%5Ctimes%20%5Cdfrac%7B4%7D%7B3%7D%5Cright%29%7D)
![\implies \textsf{Number of medium packets brought by Chas = 280}](https://tex.z-dn.net/?f=%5Cimplies%20%5Ctextsf%7BNumber%20of%20medium%20packets%20brought%20by%20Chas%20%3D%20280%7D)
Total number of medium packets of mints brought by these three shop keepers (Anne, Ben, Chas) are :
(156 + 240 + 280)
676