library PercentUtils {
    using SafeMath for uint256;

    // Return `b`% of `a`
    // 200.percent(40) == 80
    // Commutative, works both ways
    function percent(uint256 a, uint256 b) internal pure returns (uint256) {
        return a.mul(b).div(100);
    }

    // Return `a` as percentage of `b`:
    // 80.asPercentOf(200) == 40
    function asPercentOf(uint256 a, uint256 b) internal pure returns (uint256) {
        return a.mul(100).div(b);
    }
}
function asPercentOf(uint256 a, uint256 b) internal pure returns (uint256) {
    return a.mul(100).div(b);
}

// Return `a` as percentage of `b`:
// 80.asPercentOf(200) == 40