Of the 645 speckled trout in a certain fishery that contains only speckled and rainbow trout, the number of males is 45 more than twice the number of females. If the ratio of female speckled trout to male rainbow trout is 4:3 and the ratio of male rainbow trout to all trout is 3:20, how many female rainbow trout are there?  Choose the correct option:
A) 192 B) 195 C) 200 D) 205 E) 208
It will be easier if you draw a table for this one. Let T be the total trout.   total speckled trout (ST) = 645   If female speckled trout = fST   then male speckled trout = 45 + 2fST   Therefore 45+ 2fST + fST = 645   We solve and get fST = 200   and mST= 445   Ratio of fST to mRT = 4:3   We have fST = 200   Solve ratio to get mRT = 150   Now ratio of mRT to T = 3:20   We have mRT = 150   Solve ratio to get T = 1000   Now unless youve drawn the table it might get a little complex.   From above we have mST and mRT   mST + mRT = 445 + 150= 
<gadget id="calculator">445 + 150</gadget>
<output>595</output>
595   So T - 595= total female trouts   1000 - 595= 
<gadget id="calculator">1000 - 595</gadget>
<output>405</output>
405 female trouts   We have from above that fST= 200   So (whew!) fRT = 405 - 200= 
<gadget id="calculator">405 - 200</gadget>
<output>205</output>
205 answer is 205
<result>D</result>
Of the 645 speckled trout in a certain fishery that contains only speckled and rainbow trout, the number of males is 45 more than twice the number of females. If the ratio of female speckled trout to male rainbow trout is 4:3 and the ratio of male rainbow trout to all trout is 3:20, how many female rainbow trout are there?