an oil-drilling company knows that it costs $25,000 to sink a test well. if oil is hit, the income for the drilling company will be $405,000. if only natural gas is hit, the income will be $150,000. if nothing is hit, there will be no income. if the probability of hitting oil is 1/40 and if the probability of hitting gas is 1/20, what is the expectation for the drilling company?