0
Pr(At least one head in 3 tosses) = 1 - Pr(No heads in 3 tosses)
= 1 - Pr(3 tails in three tosses) = 1 - [Pr(T)*Pr(T)*Pr(T)] since the three tosses are independent.
= 1 - 1/2 * 1/2 *1/2 = 1 - 1/8 = 7/8
H. T. Lowe-Porter was born in 1877.
H. T. Lowe-Porter died in 1963.
William T. Porter was born on 1809-12-24.
William T. Porter died on 1858-07-19.