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 1. 21 2. 500% 3. 197 4. 60 days 5. Rs.42,20 6. 6²² 7. 1/2 8. 24 9 . 50% 10. 2/81

Answers with steps to Math Connect Edition 5 Questions  1. 3/9=7/X X= (9 x 7)/3 = 21 2. X% of 60 = 300 (X/100) x 60 = 300 X = (300 x 100)/60 = 500% 3. (99+98)(99-98) = 197 4. (A+B+C ) One day's work = 1/15 (A+C) One day's work= 1/20 B's one day work = (1/15)-(1/20) =(20-15)/300 = 1/60 Number of days needed by B alone to complete  the work is 60 days 5. CP=X, SP=60 P=(X/100) x X  = X²/100 P= SP - CP X²/100=60-X X² = 6000 - 100X X² + 100X - 6000 = 0 Using quadratic formula, X = (-100 +√34000)/2, (Neglect the negative value) X = (-100+184.4)/2 X = 84.4/2 X = 42.2 Rs.42.20 6. 3¹¹ x 3¹¹x 2¹¹x 2¹¹ = 3²² x 2²² = 6²² 7. (1/a) + (1/b) = (b+a)/ab = 10/20 = 1/2 8. (3+6+......+ 45)/15 = 3(1+2+.....15)/15 = (3 x 15 x 16)/ (15 x 2) ( Sum of n consecutive natural numbers is n(n+1)/2 = (3 x 16)/2 = 24 9. 80% of 60 = X % of 96 (80/100) x 60 = (X/100) x 96 80 x 60 = X x 96 X = (80 x 60)/96 X = 50 50% 10. 2/3, 10/9, 14/27, 16/81. HCF (2,10,14,16) = 2 LCM (3,9,27,81) = 81 Therefore HCF of 2/...