Take ostrich and convert to an improper fraction. Denominator times whole number plus numerator. Same with flamingo. 507/2 and 91/10 convert to like denominators. 2535/10 and 91/10. Subtract the two weights. You get 2444/10. Swing decimal one position on 2444. to get 244.4 lbs. 245 pounds is the answer since it is closest to 244.4. 253 minus 9 is 244 if you ignore fractions. Do it this way since approximation matches the answer. You can also eliminate the other answers since the difference will be less than the weight of the ostrich. Please mark as the best!
