Question

A Eugenics research worker is working with two types of bacteria. One type triples in number every ten minutes while the other one becomes $5$ times in the same time. If the total number of bacteria after half an hour is $1118$, what was the total number at the beginning ?

• A. $62$
• B. $32$
• C. $16$
• D. $64$

Answer 1

The correct option is C $16$

$27x+125y=1118$

the reminder $1118/27$ is $11$

successive multiplies of 125 the reminders$17,7,24,14,4,21,11$

$27\left(9\right)+125\left(7\right)=1118$

hence$27(9+125)+125(7-27)$expression are equal to$1118$but x is 9 and y is 8 only solution is positively charge $

$9+7=16bacteria$