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Question There are some children and donkeys on a beach. Together they have 28 heads and 80 feet. How many donkeys are there? How many children are there?
Let the number of children be x. Let the number of donkeys be y. x + y = 28 y = 28 – x ……(i) Children have 2 feet, but donkeys have 4 feet. According to the question 2x + 4y = 80 ⇒ 2x + 4(28 – x) = 80 [From (i)] ⇒ 2x + 112 – 4x = 80 ⇒ -2x + 112 = 80 ⇒ -2x = 80 – 112 ⇒ -2x = -32 ⇒ x = 16 There are 16 children, and (28 – 16) = 12 donkeys.