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## Thursday, February 9, 2012

### Social Media Math

Here are some questions that might appear in future National Assessment of Educational Progress (NAEP), Third International Mathematics and Science Study (TIMSS), or Scholastic Aptitude Test (SAT) papers, to reflect the interests or changing habits of students, who are spending an unhealthy amount of time, Facebooking and Twittering friends, fiends, or foes, rather than doing their homework.

1. N stands for the number of hours Dennis spends on Facebook each day. Which of the following represents the number of hours Dennis spends on Facebook every week?

a. N + 7           b. N – 7           c. N × 7           d. N ÷ 7                        [Grade 4]

2. If the number of Facebook members in a school is F and the number of Twitter members T, and there are 40 times as many Facebookers as Twitterers, write an algebraic equation that shows this relationship. [Grade 8]

3. For next year’s Singapore App Annual Show (SAAS), a child pays \$x per ticket and an adult pays \$y more than a child per ticket. If p children and q adults buy tickets, find the total revenue from the sale of tickets in terms of the variables. [Grade 8]

4. Sam has twice as many Twitter followers as Ruth. If Ruth has r followers and Sam s followers, and Sam helps Ruth to gain a dozen followers within a week, how many followers does each have in terms of r? [Grade 7]

5. In the following, write an expression in terms of the given variable that represents the indicated quantity.

(a) The cost of having an IT repairman spend t hours at your house if he charges \$40 for coming to the house and \$50 per hour for labor

(b) The time (in minutes) left to use the mobile phone with a battery life of 8 hours, after t minutes of SMS-es and k hours writing e-mails

(c) The resale price of a laptop after t years if its initial price is \$P and the resale value of the laptop halves every year

(d) Arthur’s total earnings as an ICT tutor after three years if the first year he earned \$x, the second year it was \$8,000 higher, and the third year it was twice as much as the second year [Grade 8]

6. Last month, Jack, a hardcore ex-convict,
· sneeringly “defriended” c Facebook members;
· insincerely clicked “Like” d times;
· angrily unfollowed e followers on Twitter;
· anonymously left f mean comments on blog posts; and
· vengefully spammed g e-mails to his ex-math teachers.

How many on-line transgressions did he commit in the last month?           [Grade 7]

7. Tom recently set up a Facebook account for his dog. Freakie has now more friends than his owner: x canine friends and y feline friends. Tom has z friends. Which of the following is true?

a. x + y < z           b. xy > z           c. x + y > z           d. z > x + y        [Grade 7]

8. @cobrakill tweeted the following to @MathPlus and @Zero_Math:

Scared off 3 bullies; had x mice & y ostrich eggs for breakfast. Gobbled up a piglet & a wild cat for lunch. And terrified a trio of oldies!

How many fell prey to the king cobra?                                                   [Grade 7]

1. c
2. F = 40T
3. px + q(x + y) = (p + q)x + qy dollars
4. s = 2r; Sam has (2r – 12) followers, and Ruth has (r + 12) followers.
5. (a) 40 + 50t dollars     (b) 480 – t – 60k     (c) P/2t     (d) 4x + 24,000 dollars
6. a + b + c + d + e + f + g
7. c

© Yan Kow Cheong, February 8, 2012.