设圆柱高为h,甲圆柱底面半径为3r,那么乙圆柱底面半径为5r,
甲圆柱的侧面积为:2×3r×3.14h=18.84rh,
甲圆柱的体积为:3.14×(3r)2×h
=3.14×9r2×h
=28.26hr2;
乙圆柱的侧面积为:2×5r×3.14h=31.4rh,
乙圆柱的体积为:3.14×(5r)2×h
=3.14×25r2×h
=78.5hr2;
甲乙的侧面积之比为:18.84rh:31.4rh=3:5,
乙圆柱与甲圆柱的体积之比为:78.5hr2:28.26hr2=25:9,
答:甲乙的侧面积之比为3:5,乙圆柱与甲圆柱的体积之比为25:9.
故答案为:3:5,25:9.