Robert Smith uses either regular plowing or minimal plowing to prepare the cornfields on his Minnesota farm. Regular plowing was used for 40% of the field acreage. Analysis after the crop was harvested showed that 50% of the high-yield acres were from minimal- plowing fields and 40% of the low yield fields were from fields with regular plowing. What is the prob- ability of a high yield if regular plowing is used? What is the probability that a field with high yield had been prepared using regular plowing