How many ways can ten pictures be arranged three at a time

This race was first held in 1953 on august 16th. every decade the race finishes with a festival. how many years is this?

Arley is building a model of a city map. in one part of the city, three roads form a right triangle, which harley draws as triangle abc, with the following measures: m∠b=90° and m∠a=30°. in his scale model, the hypotenuse of triangle abc, ac¯¯¯¯¯¯¯¯, has a length of 817−−√ cm. what is the value of a (the length of bc¯¯¯¯¯¯¯¯)?

Polynomial that can be factored as (3x-4)(3x+4)