## ________________

This week, spring is in the air.

## ________________

### Time of Day

Pretend you are in New York during daylight on the vernal equinox. You note your watch’s second hand is on a minute mark and exactly 18 minute marks ahead of the hour hand.

*What time is it?*

### The Missing Element

The open-ended sequence …35, 45, 60, q, 120, 180, 280, 450, 744, 1260… has an undisclosed element, q.

*Find a simple continuous function to generate the sequence and compute the surprise answer for q.*

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## Solutions to week 131

In Knight Trap, the knight can be trapped in **15 moves**. In My Number is 136, Ana has **135** on her forehead and Boris has **136** on his.

**Knight Trap answer explained:**

The knight can be trapped in 15 moves as shown in the figure.

**My Number is 136 answer explained:**

a = 1 and b = 135. Ana sees 136 on Boris and knows whatever product Boris sees (1 × 135, 2 × 134, 3 × 133, etc.), he can’t know his number. Boris sees 135 on Ana and considers he may have 3 + 45 (= 47 + 1), 5 + 27 (= 31 + 1), 9 + 15 (= 23 + 1), or 1 + 135. The first three possibilities are eliminated by adding to one more than a prime (which would disallow Ana from making her statement) so Boris deduces his number is 136.

## Recent Weeks

**Week 131**: Knight Trap & My Number is 136, solutions to The Size of Humanity & Fish Pond

**Week 130**: The Size of Humanity & Fish Pond, solutions to Circumnavigation & Typos

**Week 129**: Circumnavigation & Typos, solutions to Keeping Things Even & Roll Those Bones

**Week 128**: Keeping Things Even & Roll Those Bones, solutions to Race to the Gate & Tricky Logic Game

**Week 127**: Race to the Gate & Tricky Logic Game, solutions to Logical Coffee Order & Here’s Looking at You

Links to all of the puzzles and solutions are on the Complete Varsity Math page.

**Come back next week** for answers and more puzzles.