Question

In a school of student strength 500, two-thirds of the students, who do not wear spectacles do
not bring luuch. Three-quarters of the students, who do not bring luch. do not wear spectacles
Altogether 60 spectacles and do not bring lunch too. If K is the number of students who do not
wear spectacles and do not bring lunch. Then K 10 is​

Answer 1

Given : In a school of student strength 500, two-thirds of the students, who do not wear spectacles do  not bring lunch. Three-quarters of the students, who do not bring lunch. do not wear spectacles

Altogether there are 60 students who wear spectacles and do not bring lunch together

To find : K/10 , K is the number of students who do not  wear spectacles and do not bring lunch.

Solution:

Let say Students Wear spectacles  =  S

Students Do not Wear spectacles = 500 - S

Two-thirds of the students, who do not wear spectacles do  not bring lunch

= ( 2/3) (500 - S)

Students bring Lunch  =  L

Students do not bring Lunch  = 500 - L

Three-quarters of the students, who do not bring lunch. do not wear  spectacles  =  (3/4)(500 - L )

( 2/3) (500 - S)  = (3/4)(500 - L )

=> 8 ( 500 - S) = 9 (500 - L)

=> 9L = 8S + 500

Altogether there are 60 students who wear spectacles and do not bring lunch together

students who wear spectacles and do not bring lunch together = (1/4)(500 - L )

=> (1/4)(500 - L ) = 60

=> 500 - L = 240

=> L = 260

9L = 8S + 500

=> 9 * 260 = 8S + 500

=> S = 230

do not wear spectacles do  not bring lunch =  (3/4)(500 - L ) =  ( 2/3) (500 - S)

= 180

K is the number of students who do not  wear spectacles and do not bring lunch  

=> K = 180

K/10 = 180/10  = 18

Learn More

In a class number of boys is 2/3 of number of girls. Then express the ...

https://brainly.in/question/13213989

The ratio of the number of boys to girls in three classes are 7:5, 3 : 2 ...

https://brainly.in/question/20706743