In a survey of mobile and telephone, it was found that 200 people had telephone, 25 had both, 135 did not have telephone and 300 did not have mobile.
i. How many people participated in the survey?
ii. How many people had mobile only

a)660

b)135

Step-by-step explanation:

a)200+25+135+300=660

b) 135 because since 135 do not have telephone, they will have mobile instead.

Hope this helps! Thanks.

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.