An environmental agency is analyzing water samples from 78 lakes for pollution. six of the lakes have dangerously high levels of dioxin. six of the lakes are randomly selected from the sample. using technology, how many ways could one polluted lake and five non-polluted lakes be chosen?

so there are 937433448 different ways to select polluted lake and 5 for non polluted lakes

Explanation:

we will use here fundamental counting principle

and formula for combination are

    ...........................1

here n! = n ( n -1 ) . . . . . . . . . . . . . 3 . 2 . 1

so

here 78 lakes of which 6 are polluted so 78 - 6 = 72 are not polluted

so

we need select 1 of the 6 polluted

=

= 6

and

now we need to select 6 of 72 non polluted lakes

=

= 156,238,908

so

polluted lakes = 6 ways

ans non polluted lakes = 156,238,908 ways

so

fundamental counting principle

6 × 156,238,908 = 937433448

so there are 937433448 different ways to select polluted lake and 5 for non polluted lakes

question - in 1827, john walker, a druggist in a small english town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. the druggist had discovered the first friction-chemical match, the kind we use to-day. it is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. although walker's match did not require the bottle of acid, nevertheless it was not a good one. it could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. in a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. the match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. it would ignite when rubbed on any dry surface, and there was no longer any sputtering. this was the phosphorus match, the match with which we are so familiar. according the paragraph what was the benefit of the new phosphorus match? it burst into flame when rubbed on sandpaper. it was made by mixing chemicals. it could be ignited on any dry surface. it threw fire in all directions.

answer - matches required natural chemicals

answer; the parasympathetic nervous system;