- 百钱百鸡
百钱百鸡:公鸡5文钱一只,母鸡3文钱一只,小鸡3只一文钱, 用100文钱买一百只鸡,其中公鸡,母鸡,小鸡都必须要有,问公鸡,母鸡,小鸡要买多少只刚好凑足100文钱?
/*
思路:三元方程,设公鸡,母鸡,鸡仔各为x,y,z
5x < 100 => x < 20;
3y < 100 => y < 33
z = 100 - x - y
*/
for (var x = 1; x < 20; x++) {
for (var y = 1; y < 33 - x; y++) {
var z = 100 - x - y;
// console.log("x = " + x + "y = " + y + "z = " + z);
if (z % 3 != 0) continue;
// console.log("z = " + z);
if (5 * x + 3 * y + z / 3 == 100) {
console.log("result: x = " + x + " y = " + y + " z = " + z);
}
}
}
/*
result: x = 4 y = 18 z = 78
result: x = 8 y = 11 z = 81
result: x = 12 y = 4 z = 84
*/