Question

Choose​ ​the​ ​correct​ ​answer. Two​ ​pipes​ ​can​ ​fill​ ​a​ ​tank​ ​in​ ​20​ ​and​ ​24​ ​minutes​ ​respectively​ ​and​ ​a​ ​waste​ ​pipe​ ​can​ ​empty​ ​3​ ​gallons​ ​per minute.​ ​all​ ​the​ ​three​ ​pipes​ ​working​ ​together​ ​can​ ​fill​ ​the​ ​tank​ ​in​ ​15​ ​minutes.​ ​the​ ​capacity​ ​of​ ​the​ ​tank​ ​is: option​ ​1​ ​:​ ​60​ ​gallons option​ ​2​ ​:​ ​100​ ​gallons option​ ​3​ ​:​ ​120​ ​gallons option​ ​4​ ​:​ ​180​ ​gallons

Answer 1

I think it is option 2