Question 485158
A sample of 138 firecrackers contained 7 "duds".
 How many duds would you expect in a sample of 2346 firecrackers?
:
We can use a ratio equation
let d = no. of duds in 2346 f.c.
:
{{{d/2346}}} = {{{7/138}}}
cross multiply
138d = 2346 * 7
d = {{{16422/138}}}
d = 119 duds in a sample of 2346 f.c.