*{
    box-sizing: border-box;
}


body{
    background-color: lightblue;
}

#padre{
    width: 100%;
    height: 250px;
    background-color: blueviolet;
    display: flex;
    padding: 10px;
    flex-wrap: nowrap; 
}
#hijo1{
    width: 20%;
    height: 230px;
    background-color: yellow;
}

#hijo2{
    width: 100%;
    height: 230px;
    background-color: pink;
    margin: 0 10px;
}

#hijo3{
    width: 20%;
    height: 230px;
    background-color: blue;
}