ibps-so 2018 · Question 308 of 356

A rectangular eld o ered to the branch as collateral security had to be fenced before the advance against it could be released, and the valuer was required to state the cost of the fencing in his report. The eld measures 2400 square metres in area, and the length of it stands to the breadth of it in the ratio of 3 to 2, the four corners being true right angles. The fence is to be carried once round the whole of the boundary of the eld, with no gate and no gap of any kind left in it, and the contractor has quoted a rate of ₹35 for every metre of fencing put up. What will be the total cost of fencing the eld?

1. A₹6,300
2. B₹6,720
3. C₹7,350
4. D₹7,700
5. E₹7,000 Directions (Q54–Q60) : The passage that follows is taken from an essay upon the public reception of forecasts, and upon why a statement of probability is so seldom read as the statement of probability it is. Read the passage with care and answer the questions that follow it. Certain words have been printed in bold in order to help you to locate them while answering some of the questions. There is, strictly speaking, no such thing as a forecast that has been proved wrong. A forecast that assigns a seven-in-ten chance of rain to tomorrow is not refuted by a dry afternoon, any more than a coin that comes down heads refutes the claim that it was a fair coin. This is a commonplace among those who make forecasts and an irritation to very nearly everybody who reads them, and the distance between the two positions has done more harm to the standing of the science than any error of measurement ever has. The di culty is partly one of arithmetic and partly one of temperament. A probability can be judged only against a long run of cases, whereas the public meets forecasts one at a time, upon the days when it happens to have made plans. Nobody keeps a tally. What is remembered is the wedding that was rained upon; what is forgotten is the fortnight of unremarkable accuracy that preceded it. A forecaster's record can in fact be assessed with some rigour – the proper test is whether, of all the occasions upon which he said seventy per cent, it rained upon something close to seventy per cent of them – but the test requires a ledger, and a ledger requires an interest in being fair which a disappointed reader rarely has. Institutions have commonly answered the complaint by hedging, which makes matters worse rather than better. A forecast so cautiously worded that no outcome whatever could embarrass it conveys nothing at all, and its author has bought his safety at the price of the only quality that made him useful. The temptation is strongest exactly where the stakes are highest. An o ce that has been censured for one storm it failed to announce will issue warnings for the next several, most of which will come to nothing; and the public, which learns quickly, will discount such warnings altogether by the time one of them matters. The cost of a false alarm is not paid at the moment it is raised. It is paid afterwards, in the currency of inattention. What is asked of the reader is not a course in statistics but a small alteration of habit: to treat a forecast as a statement about a range of possibilities rather than as a promise, and to observe that the width of the range is itself an item of information. A warning that a river may rise by between one and two metres says something wholly di erent from a warning that it may rise by between one and six, although both may appear beneath the same headline. Broadcasters compress the two into a single gure because a single gure is what the format will carry, and the compression, rather than the science, is where most of the meaning is lost. None of this is peculiar to the weather. Any body obliged to speak publicly about the future – a central bank publishing a projection of prices, an engineer estimating the life of a structure, a planner counting the population of a city twenty years hence – meets the same three pressures: to be de nite, to be safe, and to be honest, of which no two are easily reconciled. The only durable answer anybody has yet found is the tedious one. Publish the record, keep the ledger where it can be inspected, and let the reader discover for himself how often the seventy per cents came true.Correct