Xiao Ming went to his grandfather's house by bicycle, and his grandfather went out to meet him. After a while, his grandfather met an oncoming car. He asked the driver if he saw a little boy riding a bicycle coming this way. The driver said: "Yes, I passed him 8 minutes ago". Grandpa continued to walk, and met Xiao Ming after walking for 20 minutes. It is known that Xiao Ming’s speed is 4 times that of Grandpa’s, how many times is Xiao Qiao’s speed faster than Xiao Ming’s?
小明骑车去爷爷家，爷爷出门去迎接他，行了一段时间，爷爷遇上一辆迎面开来的小轿车，爷爷问司机，有没有看到一个朝这边来的骑自行车的小男孩，司机说："有，8分钟前我超过了他"．爷爷接着走，走了20分钟后与小明相遇．已知小明的速度是爷爷的4倍，问小桥车的速度是小明的几倍？
<result>4.125</result>