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,
· illegally downloaded a pirated blue movies;
· secretly watched b YouTube adult-themed clips;
· 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. x – y > 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]
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
6. a + b + c + d + e + f + g
© Yan Kow Cheong, February 8, 2012.