kindly solve these math problems for me......

[anam]

1) five identical balls are merked with the numbers: 7, 3, 4, 2, 1 and are placed in a box. the balls are thoroughly mixed before three balls are drawn out all at one time from the box. A score is obtained by adding the numbers on the three balls drawn. find how many different scores are possible and the possible score.

2) a passenger train travelled at a speed of 72km/h. a man on the passenger train observed a goods train travelling at a speed of 54 km/h in the opposite direction. if the goods train passed him in 8 secs, find the length of the goods train.

give explanatory solutions plzzzzz

 

[zain555]

Q2) think of this as passenger train stationary and only goods train moving.
so the total speed will be v=72+54=136 km/h
its takes train 8 secs to pass, convert this time to hours as speed given in km/h
in order to convert secs to hours divide it by 3600
so distance covered d=136*(8/3600)=0.302222 km
u can convert it to meters if u want by multiplying by 1000
length 0.30222*1000= 302.22 m

 

[williamjacob]

There are exactly twelve children in Ryan’s class. Only four of the children are boys. The following questions refer to a time when all the children are present in the class. There are no visitors in the class. There might be more than one correct anwer to a question.

1. Which of the lettered statements must be true?

2. Which of the lettered statements cannot be true?

3. Which of the lettered statements could be true or not true?

a. There are twice as many girls as boys in Ryan’s class.

b. There are eight more girls than boys in Ryan’s class.

c. There are four more girls than boys in Ryan’s class.

d. If Ryan is sitting at a table with all the girls, there are exactly nine children at that table.

e. If only three of the boys are standing on their heads, one of the boys is not standing on his head.

 

[dukeunique]

well iam confused in this dude