Please help I have ALOT of questions!!

1.)Starting at 888 and counting backward by 7, a student counts 888, 881 and 874, and so on. Which of the following numbers will be included?

a) 35 b) 34 c) 33 d) 32 e) 31

Ok, so I by using the calcuator the aswer is 34, but how would you calcuate this using an equation or something more sensible...

I think I have to use this one

tn=a + (n-1) d

a= 888

n=

d= -7

tn=

... now what

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2. the sum of the first n even postive integers is h. the sum of the first n odd positive integers is k. then h -k is equal to:

a) n/2

b) n/2 -1

c) n

d) -n

e) n - 1

so... nK and nh

I don't get it...

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3. the largest four- digit number to be foung in the arithmetic sequence

1,6,11,16,21, ... is

t1= 1

t2= 6

t3= 11

t4= 21

9996?

because it goes form 1 to 6 the (last number)

2nd last number stayes for 2 ed 1,1,2,2

everything else up one

but is there an equation for this or something?

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4. the sum of 50 consecutive intergers is 3250. tha largest of these intergers is

a)64

b)66

c)112

d)114

e)115

I don't know how to so this...is it the same as before?

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5 Jan 1, 1986 was a wed. Jan 1 1992 was waht day of the week?

86 wed

87 thurs

88 fri

89 sat

90 sun

91 mon

92 tues

tuesday?

what would an equatin be

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6) The total number of digits used to number all the pages of a book was 216. Find the number of pages in the book.

tn= a + (n-1) d

216= 1 + (n- 1) 1

216= 1 + n - 1

216=n

is that wrong...

so...

total number of digits? sum?

Sn= n/2 [ 2a + ( n-1) d ]

216= n/2 [ 2(1) + (1-1) 1]

216= n/2 (2)

216= n

umm....?

Pleas help!

thanks

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