math problem of the day

in an effort to stave off complete brain decay, i decided yesterday that it would be beneficial to work some basic math problems every day. i figured google could spit me out some algebra worksheets or somesuch - something of the type traded around online by grade school teachers who for whatever reason can't come up with their own damn stuff. thanks, lazy teachers, for facilitating the preservation of my brain.

so i googled "math problem of the day", and what to my wondering eyes should appear but "math problem of the day"! right there at the head of the results list.

here - you can go there yourself:

math problem of the day

so. at "math problem of the day", there is a math problem for each grade 1-8. hey, now. i can COUNT. there are EIGHT problems per day! bo-nuuuus!

i was thinking maybe the levels 7 and 8 might be challenging but 1 through 6 would be a piece of pi. (1) HAHA. piece of pi! get it?? (2) HAHA. easy! i thought they would be easy!! hahaha...

here are the problems from today:

1. Mini's house number has three digits. The middle digit is more than 6, but less than 9. Which of the following could be the middle digit?

2. Jesmine has three number cards with numbers 1, 3 and 9 and she wants to arrange them to make the greatest number. Which of these is the greatest number she can make with these cards?

3. In a certain code language, BLUE is written as CLUE and RAT is written as SAT. How will the word BUT be written in this language?

4. Robert has invited two of his friends to his house. He wants to buy a Pizza, three packets of chips, and three cartons of juices for the occasion. One carton of juice costs $10. The pizza costs 6 times as much as one carton of juice and the cost of 3 packets of chips is $36. If Robert has $100 with him, how much more money does he need?

5. A man bought 5 kg of rice at $100 and sold it at $160. How much profit did he make per kg of rice?

6. he sum of the ages of Peter and his sister is 23, and the product of their ages is 130. What is the difference between their ages?

7. Kiran walked 6 km in 50 minutes and then took a bus to travel the next 14 km in 20 minutes. If his journey continued in the same pattern alternating between walk and bus, how much time will he take to cover a total of 80 km?

8. In a hostel, there was enough food to feed 120 students for 6 days. If 30 students left the hostel to go home for vacation, how many days will the supplies last for the remaining students?

grade 1. right away i'm all confused by the verbiage, but i took a breath and read it again verrry slowly and perused the choices, and located the correct answer. okay. passed the first grade.

grade 2. easy peasy. 931.

grade 3. again, easy peasy -- although their solution described a code which replaced the first letter of a word with the next letter of the alphabet, and i had just assumed "replace b with c" and would have been screwed if they'd given me FISH.

grade 4. omg, how much does a damn pizza cost?! but then i saw it's not pizza, it's Pizza, and i know name brands always cost more. anyway, save your money, bob. your friends are NOT worth it. i got through this one fine - just tallying up the charges - and determined ol' bob needed to take out a second mortgage to have a few friends over.

grade 5. simple. $60 profit divided by 5 = $12 per kg.

grade 6. this one had me stumped. i tried P+S=23 and P*S=130, then (23-P)*P=130 and pretty soon i was on the road to a quadratic equation. what the hell? i ended up just plugging in some damn numbers until i got to the answer. that is obvs not the recommended method. the recommended method involves finding factors of 130 that add up to 23. OH, RIGHT. anyway, i got it correct and i did even more work than required, so obvs that's bonus points for moi.

grade 7. easy peasy. write "6, 50 -- 14, 20" in columns down the page until you get to 80 on the 6 & 14 side, then add up all the 50s and 20s. i am certain there's a formal method (i.e., formula), but i have fingers and toes to count on -- i don't need no stinking formula!

grade 8. easy! i just subtracted 30 from 120 to get 90 and did a proportion. 120/6=90/x. 120x=540. x=4.5 days, right? right. except for the little detail that the closest available multiple choice answer is 8 days. fucking hell. i guessed 8 and got it right.

100% overall!

so, my brain isn't dead, but damn it's rusty. i was using all the tricks i could come up with plus some really lame tallying and guessing.

oh, by the way... their solution to grade 8: "The supplies could feed 120 students for 6 days. If there was only one student, the food will last 6 x 120 = 720 days. After 30 students leave, there are 120 - 30 = 90 students remaining. For 90 students, the food will last for 720/90 = 8 days."

ugh. there are a couple months' worth of "math problems of the day" between me and that solution.