The missing length is 12km (i never promised anything xd)
Answer:
The answer is 17.2 hours
Step-by-step explanation: Because first you add all hours together (which is 86/15) then multiple it by 3 (week) which is 86/5 = 17.2 hours
There are 2,000 fifties in one hundred thousand
Calcualate 40% (0.40) times 20 to get that there are 8 boys in the class. The rest must be girls, so 20 - 8 gives you 12 girls. 25% (0.25) times the 8 boys gives you that 2 of the boys wear glasses. 50% (0.5) times the 12 girls tives you that 6 girls wear glasses. Add together the 2 boys and the 6 girls that wear glasses to get that a total of 8 students wear glasses.
