Mr. and Mrs. Boyd Knevel use a scal year ending July 31 as the taxable year for

Mr. and Mrs. Boyd Knevel use a fiscal year ending July 31 as the taxable year for filing their joint Form 1040.
a. What is the last date on which the Knevels can apply for an automatic extension of time to file their return for fiscal year ending July 31, 2015?
b. Assuming that the Knevels make a timely application, what is the extended due date for the return?