Measures of central tendency task cards

What signals you that factoring by grouping is the best method to use when factoring a problem?

Afactory buys 10% of its components from suppliers b and the rest from supplier c. it is known that 6% of the components it buys are faulty. of the components brought from suppliers a,9% are faulty and of the components bought from suppliers b, 3% are faulty. find the percentage of components bought from supplier c that are faulty.

Write an inequality for this sentence the quotient of a number and -5 increased by 4 is at most 8