Level 2
There are some cows and ducks at a farm. There are thrice as many ducks as cows. The total number of legs from the cows and ducks is 60. How many cows are there?
Level 3
Steven and Ting Ting shared 400 cubes equally. After Steven gave away some cubes, Ting Ting has 8 times as many cubes as Steven. How many cubes did Steven give away?
Level 3
Ken had 6 times as much money as Andrew. After Ken had spent half of his money, he had $34 more than Andrew. How much money did Ken have at first?
Level 3
Min and Tina had an equal number of candies. After Min bought another 20 candies and Tina bought another 6 candies, Min had thrice as many candies as Tina. Find the number of candies each of them had at first.