Lin and Jen each thought of a number. Lin thought of a 2-digit number. Jen’s number is 7 times as big as Lin’s. But, if Lin writes 0 between the digits of her number, she’ll get Jen’s number. What are the numbers?
Lin's number is 15 and Jen's number is 105. 15 is a two digit number and if we multiply it with 7, we get the answer 105. 15 x 7 = 105 And if we put 0 between the Lin's number that is 15, we will get 105 Thus, 15 and 105 are two numbers.
Let xy be the number of Lin. (x and y are the two digits) Jen's number equals then 7(xy). Add zero between the two digits of xy we get x0y. And then we get x0y = 7(xy). From the above equation we deduce y = 1 and also 7*x=x0 then x = 10
(please note, 10 is not a digit, but the equation has no solution otherwise )
